Ubuntu Hardy Repositories list

The simplest and safest way to install software in Ubuntu is to use the apt-get. But for it to work you need to know two things - you need to know what do you want to install, and you need this piece of software to be available in your repositories list.
Unfortunately, not all software that you may need is available in the default repositories. Usually this means that you need to go and look for a repository - most of the time it is enough just to google the program name, but there is a easier way. You can download a custom repositories list, and then to use it instead of your default one.

Photo by rafa espada

There are two problems with this method, however. First of all installing packages from not official repositories may break your system. This is especially true when your are upgrading to a new release. The second problem is that some of the repositories use GPG keys. In order to use them you will need to find the keys on your own. This is easy to do, most of the time a search for the repostory name will aso find the correct command for getting the key. Also, I include most of the keys in the file, so you will only need to download them. But this is very time consuming.

If this doesn't scare you away - click to download a large Hardy repositories list.
Update: Some of the repositories in the original list are outdated. Click here to download an updated version of the list. It is smaller, but all the repositories in it are working
Update 2: An even newer list, get it here.
To install it run these commands in terminal:

sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup
sudo cp $HOME/sources.list /etc/apt/sources.list
sudo aptitude update
sudo aptitude upgrade

After this, check the errors that the apt-get update commend will return, and add the keys for the repositories. In order to do this you will need to find the key to the repositories (it is listed in the sources file) and then run the following commands (replace KEY with the key listed in the list):

sudo gpg --keyserver subkeys.pgp.net --recv KEY
sudo gpg --export --armor KEY | sudo apt-key add

It will take a lot of time, but after this you will have a lot of extra repositories available. If at some point you will no longer need the extra repositories, or will want to remove them temporaly from the source file you can just run the following command:

sudo cp /etc/apt/sources.list.backup /etc/apt/sources.list

If you know a repository not mentioned in the list you are welcomed to share it in the comments...

The largest jokes of nature..

It is a sad video - most of the people shown in it suffer from some sort of genetic problems, or just from the results of a wrong life style. It is interesting to watch, and it is even slightly funny - but I really doubt that anyone will watch it twice.

In the case you are wondering who made this video - it was done by this StumbleUpon user.

Also, for those who like large things - a list of World's largest useless things.

Ubuntu Hardy is out - what to do now?

Another milestone is reached - a new and improved version of Ubuntu is out. The question is - should you install it? I am a bit surprised myself that I actually wrote this question, but there are some things to consider before installing this upgrade.

What you will get with Hardy:
1. A lot of small improvements - while they are not visible, they contribute to the system overall stability.
2. Improved GUI - there are nice changes, but they are not turned on by default. You can read more about them in my post Thoughts about Ubuntu Hardy - GUI.
3. Latest versions of Firefox, OpenOffice etc.

Unfortunately, this is all. While there is nothing wrong with this upgrade, I don't see that it gives much the changes for the user are relatively small - this is mainly a stability update.
Moreover, there are two things to consider before upgrading to Hardy:
1. I installed the beta version and the update didn't go too well. There was a bug in the install process that caused the sudo command to stop working - when trying to run sudo I got the message "unknown host". The fix is to change the hosts file (it is located at /etc), by adding your desktop name to the list. The catch is, to edit it you need to be root. I solved it by typing aptitude into terminal and then it is possible to become root using the action menu. After doing so it is possible to use gksudo from the terminal. You can read more about how the upgrade went in the Upgrading to Hardy post.
2. The default browser, Firefox, is a beta version. This means that not all of your extension will work. It is possible to solve this partially by installing Nightly tester tools extension. Using this extension you will be able to use add-ons that are not compatible with the version of Firefox you have, but they are not guaranteed to work. If you use Firefox a lot, and especially if you have a lot of add-ons this might be a problem.

Also, if you use kiba-dock be warned - it will not work after the update. It is possible to install it in Hardy, but it must be compiled from source. You can read how to do this in my post Installing kiba-dock in Hardy.

Adding style to Firefox

One of the greatest advantages of Firefox is that it can be customized very easily. There are already a lot of extensions for it, and also a lot of scripts to further modify the browsing experience. I already wrote about this in the post Modifying the net. In this post I want to highlight another useful extensions (found it last week..) Stylish. This extension is a script manager, just like Greasemonkey.

Just as with Greasemonkey, there is a large collection of scripts available to download from UserStyles. I am now using three scripts. The first one is for Gmail, it is called Gmail Redesigned. (Update: This script is no longer available for stylish, read this post to get it: Google Redesigned). I always liked the default view of Gmail, but this little script managed to improve it significantly. Before and after pictures:




The other two scripts are so called global scripts. One of them is for centering the images on the screen - it works only when you open an image in Firefox. It is hard to say if it is actually useful or not, but somehow it looks more natural when the image is in the center of the screen. You can download it here.
The last script modifies the default blank page. This is how black pages look after installing this script:

I tried to find a nice script for GReader, but failed. Some of them looked very nice but they all totally broke the page - probably this is because I am on the latest Firefox beta now.

Firefox Easter eggs

I new about one of them for a long time but apparently there are three. Firstly, type "about:mozilla" without quotes in the address bar. You should see a page with a citation from the Book of Mozilla. In Firefox 2 we got this text:

And so at last the beast fell and the unbelievers rejoiced. But all was not lost, for from the ash rose a great bird. The bird gazed down upon the unbelievers and cast fire and thunder upon them. For the beast had been reborn with its strength renewed, and the followers of Mammon cowered in horror.

From The Book of Mozilla, 7:15

In Firefox 3b5, the text is different:

Mammon slept. And the beast reborn spread over the earth and its numbers grew legion. And they proclaimed the times and sacrificed crops unto the fire, with the cunning of foxes. And they built a new world in their own image as promised by the sacred words, and spoke of the beast with their children. Mammon awoke, and lo! it was naught but a follower.

From The Book of Mozilla, 11:9

(10th Edition)

Photo by Sleestak66

There are also two other easter eggs. If you will type "about:credits" you will get a list of all the developers who contributed to the project. Surprisingly there is at least one name for every letter - even one for Q..
The last egg works only in Firefox 3. Type "about:robots" to get this:

Click on the "Try Again" button for an extra joke..

Also try to type "about kitchensink" (without semicolon and quotes). This is not Firefox Egg, it is just a redirection by Google, but it is still funny..

Bonus: If you have Picasa, open it and press Ctr+Shift+Y. A teddy bear should appear on the screen. Apparently it belongs to one of the developers... if you will continue to press the key combination you will get more teddy bears.

Free ClipArt

I never liked ClipArt too much - its quality is usually too low for any serious use. However when I saw this post, I knew that I will almost surely find something for me to use in this 800 mb collection. Besides, all the images are public domain which means it is possible to modify them and to use for any purpose.
The post was changed since I first read it - it now says that it is possible to download the collection using apt-get.

Just a small example of what is inside...

When I first saw it, it provided a direct link to the archive. If I understood correctly, not all ClipArts that are in the archive are available via apt-get. To get the archive do the following:

For Linux:
Open terminal and type (one line at a time):
mkdir ClipArt
cd ClipArt
wget http://download.openclipart.org/downloads/daily_SVG_snapshot.tar.bz2

For Windows:
Download the archive.

It is a large download - 156 mb. After unpacking it will take about 800 mb. I downloaded the entire collection today, and deleted all the pictures I didn't like - what remained was 15 mb in size - 5 mb after putting it into a zip archive. You can download it here.
Please note that all the ClipArts are in svg format. If your computer cannot open this file type, and you don't know a program that will open it, you can download a smaller archive with png images here.

Azereus frog

FAQ and how to contact me

This post is a work in progress. Probably I will be able to expand it as times goes on..

Q: Who are you?
A: I don't like to share information about myself. If you have a reason to know something (curiosity is not considered a reason) it will be told personally and not discussed on this blog. What I want the world to know about me is written in the "About me" page section to the right.


Q: Why you started this blog?
A: To be honest, I hoped to get income from it. Very soon I understood that it is not very real. As of now I write this blog for myself. It turned out that I like writing posts...


Q: Do you have any connection to MathPages.com? Why you have the same name?
A: I have no connection to it. You can read more about this here.


Q: Why there are birds in Math Pages blog header image?
A: When I draw this image, I wanted to add something to its right side in order for it to look more filled. I am using Gimp for photo editing, and it turned out that one of the built in figures it can draw is a bird. I have nothing against birds, so I added their shapes to the header. Overall I am pleased with the result.


Q: Why you write "math"? You should write "maths".
A: No. There are two ways of writing it. If you are from UK you probably write "maths" but in the USA it is written "math". Also - see the Wikipedia article.


Q: I have proved the Riemann Hypothesis / developed a GUT theory, but nobody takes me seriously. Can you help?
A: Short answer - no. Long answer - firstly go here and then here. If after reading these two pages you are still confident in your ideas use my e-mail (below) to contact me.

Q: I have a blog/site, and I want you to add it to your blogroll (or to mention in a post).
A: I add only math blogs (I have a few non math blogs there, but if you are not a math blogger it is unlikely that I will include your blog there). Also, I want to be sure that the blogs I have in my blogroll add something to my readers, so I firstly subscribe to them myself and then if I like the content I add it. So the best way to get in there is to simply notify me about your blog, if I will like it I will add it myself. I am not going to add your blog because you added mine to your blogroll.
A site I cannot add to a blogroll, but if it is interesting or useful I will write a post about it.

Q: How can I contact you?
A: The best way is to use e-mail. My e-mail address is:

Blog and commenting policy

It is a bit strange to have a policy for a blog I suspect, but I do feel that there is a need in it (if not now then perhaps in the future). This post will be edited slightly from time to time.

Blog topic
It is very easy to see that this blog is not very focused. From its title it appears to be a math blog, but the topics I cover on Math Pages are broader. I often write about physics and computers (mainly about Linux and internet news). There are two main reasons for this. First of all, while I study math I also do some physic courses and I am very interested in physics. The same is true for computers. Secondly, I don't have a list of topics to write about. I just write about what interests me. This blog, together with my StumbleUpon blog cover most of my interests in terms of topics. By not focusing this blog on one subject I make it easier for myself to come with ideas to write about.
I hope that what I write will be useful and interesting for other people, but I blog for myself not for you. So while you are all encouraged to comment or even to ask me to write about specific question, I am not going to listen to claims that I am "too far of my blog topic".

Comments
In math comments should be encouraged, in my opinion. You are all welcome to comment on any post I wrote on this blog as long as your comment is not spam or uses offending words.
To be slightly more specific - comments that contain the following will be deleted:
1. Links to dangerous sites - sites that try to install malware of any sort.
2. Links to sites that are considered dangerous by Google - I know that there are sites in this list that were compromised once, and are no longer infected. But as long as they appear as dangerous in Google database I will consider them as such. I am not going to try and do investigations.
3. Personal attacks. If you disagree with me or with someone else do it politely.
4. Links to sites unrelated to the post topic, unless it is your site and is linked from your signature and not from within the comment itself.
5. Links to adult sites.

Guest posts
If you want to write a guest post on Math Pages, use my email to contact me. Basic rules are as follows:
In the post you will get a link to your blog (or any other site as long as it is not adult or infected with malware), your name will be clearly indicated and if you want a short (one or two sentence) description of yourself (or your site/blog) will be added.

Installing Kiba-dock in Ubuntu Hardy

I know I said that I will try to post more about math, and I will do this. But for some reason the topics I feel a desire to write about now have a rather week connection to math. Anyway, Math Pages is not only about math, it is also about physics and computers so I don't think that I am going too far away by posting about my experience with Ubuntu Hardy. This post is a short guide for installing Kiba-Dock in Ubuntu Hardy.

For some reason Kiba-dock is not in the official repositories. Moreover, it is not available in any other repository I know about, except for Trevino. But the version in there doesn't work on Hardy.
This means that the only way to install it is to build it from source. Gladly this is very simple to do.

First of all you need to make sure you have all the required packages. Type the following in the Terminal:

sudo apt-get install fakeroot automake1.9 build-essential libpango1.0-dev libgtk2.0-dev libgconf2-dev libglitz-glx1-dev librsvg2-dev libglade2-dev libxcomposite-dev subversion libtool libgtop2-dev python-gtk2-dev libgnome-menu-dev libgnomeui-dev libgnomevfs2-dev intltool libxml2-dev libglitz1-dev libcairo2 libdbus-1-dev libgtop2-7 libgnomevfs2-0 libgnomeui-0 librsvg2-2 python-feedparser libasound2-dev libsdl1.2-dev libdbus-glib-1-dev libgstreamer-plugins-base0.10-dev libgstreamer0.10-dev libgstreamer0.10-0 pidgin-dev libpurple-dev subversion

Now we can download the code:
svn co https://kibadock.svn.sourceforge.net/svnroot/kibadock/trunk/ kiba

A new folder "kiba" should appear now at your Home folder. All what is left to do is to compile all the components one by one. The order of compiling is important - you need to build akamaru firstly, then the dock and then the rest. You can do this either manually or by using the script linked in the end.
To compile akamaru type the following commands (one by one):
cd kiba/akamaru
./autogen.sh
make
sudo make install
cd

Now you need to repeat it for the rest. To do it simply replace "akamaru" in the first line with the appropriate folder name. Alternatively, you can download this little script (you will still need to install all the required packages firstly for it to compile). In order for it to work you need to make it executable. To do this right-click on it and go to Properties ->Permissions ->Allow executing file as program. This is all - just open it and select Run or Run in Terminal - it will take a few minutes to complete.

Update: It might be useful (especially if you did a clean install of Hardy) to add extra repositories to your default list. You can read my post Hardy Repositories for instructions on how to get a large repository list, with all the required keys.
Update 2: Programs that were installed using the make install command cannot be removed using apt-get or synaptic. If for some reason you want to remove or reinstall Kiba-dock follow the instructions in the post Uninstalling Kiba-dock.

Thoughts about Ubuntu Hardy - GUI

As I wrote in the post Upgrading to Hardy, I decided to go and try the beta version of Ubuntu. It is a bit of a surprise but apparently the main changes in this release that are visible to the user are GUI improvements. There are of course many other changes, but the amount of small but very noticeable visual changes is somewhat unexpected.

The first such change I noticed is that when I click on a launcher it "pulses". I wanted to include a video of this happening, but the program I usually use for this refuses to work in Hardy, for now at least.
The effect itself is nothing new, it was available in kde (but not in Gnome) before. However this is a nice improvement. It is very easy to see now on which launcher you clicked - people with weak eyes will like it especially.

Another change is a bit unofficial. For a long time the default theme in ubuntu was "Human". They changed it to "Human-Murrine" at some point, and then reverted back but kept the new theme available in the Appearance manager. The main changes can be seen in these screenshots:

The scroll bar is orange now, and the buttons have more blur.

Selecting a button in Nautilus

A new progress bar style

My personal impression from this new theme is very positive. I liked the old one, and yet I see this one as an improvement. Except for the orange scroll bar...

Anther small change is that the 3D windows plugin for compiz finally started to work. It didn't work for me on gutsy, but it started to work after the upgrade. Unfortunately not all is well with compiz even now. Two days ago after I installed some updates compiz refused to work. For some reason there was a dependency problem which caused synaptic to remove the compiz package. I fixed it but adding two extra repositories:
deb http://ppa.launchpad.net/gilir/ubuntu hardy main universe
deb http://ppa.launchpad.net/mvo/ubuntu hardy main
Compiz is working now but not emerald - I don't care much about it, so it is not fixed yet.

Another change is the addition of Screenlets to the repositories. The version in the official repositories is not the latest - you will need to add the repositories mentioned above for the latest version (and yes the changes worth it). This is how my desktop looks like now:

Front view

Side view - using desktop cube

There are two other photos (where the squares are), but they are copyrighted so I put a pattern on them.
The two photos that are visible are in fact slideshows - I have a collection of over 200 photos I found on the web, so I configured these two slideshow screenlets to show this photos at 10 seconds intervals.
It is also possible to put some or all screenlets into a widget layer provided by compiz. All you need to do is to enable this layer in the compiz manager, and then to choose the widget option for the screenlet (right click on it and then click window->widget).

Overall I think I like all these changes - they make the system look nicier. Hopefully Ubuntu will be able to continue with this trend of improvement in the future.
For those who bothered to read this post to the end - a little bonus. I just discovered it is posible to view Star Wars for free in the terminal. All you need to do is to type this comand:

telnet towel.blinkenlights.nl

Color not included.

Micro black holes

While this subject sound like something not very real (and for a good reason) it became somewhat important to the general public in the last years. The reason for this is the Large Hardon Collider - LHC. While it is still only a theory, many people think that it might produce micro black holes that would destroy our world. I already wrote what I think about this danger in the post The horror of LHC. There is simply no reason what so ever to expect that these black holes even if they will be created will posses any danger. You can also read more about it this nice article: Help! A black hole ate my lab.

On a more general note, I never managed to understand why people who clearly don't have even basic knowledge of physics tend to speak their opinions about it so loudly. It doesn't happen only in this field of science of course, but why does it happen at all? It is how the world works I guess...

I am now on winter vacation - this means that I have more free time, but I also have a lot of stuff to do. Hopefully I will manage to keep this blog updated with more math related content, for some reason I didn't wrote about math for a long time...

Modifying the net

The internet is a great tool, both for research and for procrastination. But as any other tool in order for it to be used with maximum effect, we need to know how to use it and how to "modify" it according to our needs. This post is a short overview of the ways we can modify how the web looks and works for us - unfortunately most of the tools discussed here requires Firefox, sorry IE users..

Photo by Lida Rose

Search:
If we want to find some information we usually use Google or another search engine. It is possible to modify the results a search returns, so that it would be easier to find what we are looking for.
I currently use four extensions to achieve this.
Googlepedia - it is a Firefox extension that shows a relevant Wikipedia article on the right side of the screen.
Customize Google - removes ads from the search results (can also remove ads from Gmail and other Google products), and adds links to other search engines. It also can stream search results, thus eliminating the need to go to the next page.
StumbleUpon - it can be used as a search engine on its own, but it also can show reviews of the results shown by Google. If you have friends on SU it will also show who of them liked the page you see in the search results. This is especially good if you have a lot of friends with similar interests on SU.
Google toolbar - One of the most useful features of this toolbar is its ability to highlight your search terms on a page you visit. Unfortunately it doesn't work in Firefox 3 beta - without it I find it much more difficult to search for things on the net... Hopefully Google will release an update for it soon...

Ads
For me it is almost a thing of the past. Since I installed Firefox and ad-block, I almost never see any ads. You can read more about it in my post "I like ad-block plus".

Portals/Often used sites
We all have something set as our homepage. I personally use iGoogle. I find it both useful and having a nice layout. However just as most of the other sites on the net it isn't perfect. One example of this is its footer - it has ads in it and it just takes unneeded space.
There is a simple way to get rid of such annoyances - all you need is to install a Firefox extension called Greasemonkey. This little program allows you to use scripts to modify how a web site will look to you. There are a lot of people using it, and a lot of them don't mind sharing the scripts they wrote with the rest of us - most of these are available on UserScripts.org.
If there are no scripts for your favorite website, or none of them do what you want, you can always write one yourself. There is even a program for helping with this - Platypus. It can be regarded as a visual editor fro the web I guess... I used it to add a rss subscribers counter to my iGoogle homepage, for example. It is very easy to use.

The horror of LHC

At this point almost everybody knows what LHC is. There is more than enough media hype around it, and especially around its "danger to the whole planet". There is even a lawsuit about it already... While it is nice that people who are far from science are interested in this topic, it is a bit annoying when people try to give advice without even understanding the subject they are speaking about. Unfortunately, this is exactly the case with the LHC.

According to the media, there are two ways in which LHC can destroy our planet: by creating micro black holes (that would tear the planet apart) or by creating a so called "strange matter" capable of converting our planet into a "strange star". I am not going to attack the people who are behind this ideas, but I do think that this ideas don't have a sufficient logical basis.

Lets examine both of the ideas.

Micro black holes: It is not yet even an accepted theory that they may be created in the conditions provided by LHC. It would be wrong to disregard it because of this, but even if such holes will indeed form there is no reason to be afraid from them.
Black holes are dangerous because of their gravitational pull. This pull is so strong that even light cannot escape the event horizon of a black hole. But why black holes have such a strong gravitational pull? In order to have gravity you need mass, the bigger the mass the more force you will get. The cosmic black holes we often hear about have the mass of at least 3 suns (this is the theoretical minimum, usually they are much large). LHC is not capable of creating such a cosmic black hole - it would require a totally insane amount of energy.
Micro black holes are very different from the cosmic black holes. Their mass is very small, and they also don't light escape their event horizon. How they manage to do this if their mass is very small? The answer is very simple. A black hole must satisfy the following equation (more precisely it should be less than and not equality) :

0.5c^2=GM/R

R - radious of the black hole. M - mass of the black hole. G - gravitational constant. c - speed of light.
Any object that satisfies this equation is a black hole. G and c are constants, M is the mass of the micro black hole created by LHC and is therefore also unchangeable. So the only way to create a block hole is by making the radios smaller. The micro black holes are nothing more than a very, very well compressed matter.
LHC is capable of very high energies but they are very small when compared to mass energy.. The energy needed to produce even 1 kg of matter is much more that what is LHC capable of.
Even if a micro black hole would be produce this way it would have no impact on the world around. More precisely, the effect of such a block hole on the objects around it would be exactly the same effect its mass was causing before it was compressed. Noticeable difference would be visible only a very tiny scales - radius of an atom for example. Creation of such a black hole, if it is possible to to create a all, would in no way harm the world - unless it will start growing.
It is very easy to prove that this will not happen, but it is more difficult to understand. The reason is the same as with the "strange matter" .

Strange matter : First of all it is a totally theoretical object. It was never seen, not even in a lab. This is not enough to say that it doesn't exist, but it is enough to say that LHC will not produce any. This is so because LHC energy is much lower than Cosmic rays energy. If it is possible for LHC to destroy the earth by producing micro black holes or strange matter, so it is for these rays. Since we are still not destroyed, there is no reason to worry.

Upgrading to Hardy

I guess I love living on the edge - but only when it concerns installing beta software on my computer.. As I wrote in my post Why I use linux, my main OS is Ubuntu. A few days ago I finally upgraded it to the latest version - Hardy (it is a beta version now). As always with major upgrades, it it both funny and a bit annoying until you get used to the changes.
This post is about how the upgrade went and my thoughts about Ubuntu Hardy.

Photo by zone41

Upgrade
One of the reasons I decided to install the beta version was that if you download the beta version it takes less time to download. Ubuntu is a very popular distro, so when they roll out major upgrades their servers are totally overloaded. It is of course not very recommended to install beta software, but I already did it too many times so I saw no reason to worry. I also read a very positive review on Tombuntu - this is my second reason for upgrading. Without it I doubt I would take the risk to install a beta OS, when I need to work on my computer and don't have time to fix it if something goes wrong.

Unfortunately, the upgade didn't go too well. It ended up with this message: "Your system may be broken."
Not something you want to see after installing an OS... Thanks God it wasn't too horrible. I restarted the computer, and everything seemed to work just fine. Then I noticed that sudo was not working. If I tried to do anything that required super user privileges (due to the way I connect to the internet, I need sudo to work in order to be able to connect to the internet), I just got the following message - "unknown host". It turned out that the upgrade changed my hosts file. Sudo apparently used it to check on what computer it is running, and my computer didn't appear there. It is very easy to fix - but you can only edit the hosts file using sudo. Thanks God it turned out that sudo wasn't completely broken. Accessing synaptic in terminal and than becoming root from there, somehow allowed the graphical sudo - gksudo command to work.

New applications
I am not sure if it correct to say that Ubuntu 8.04 is a lot better than the previous version. But there are definitely changes. Unfortunately, most of the things I noticed so far are more like problems...
Firefox
The main change for me is that Firefox 3.0 is the default browser now. Web browser is the most used program on my computer. There are a lot of visible changes in Firefox 3.0. It is faster, and the GUI is prettier. The most important change is that finally you can install extensions without going to their site - all you need to to is to start the add-ons manager and do a search for the extensions you want to install. There is also support for a new graphic format APNG.

If you are using Firefox 3 you should see the Firefox logo spinning.

However, this upgrade to Firefox 3.0 is causing me a lot of problems. Not all my extensions work in FF3. Some of them are simply incompatible - it is possible to use them anyway if you turn off the compatibility check. This is very easy to do, you just need to install the Nightly tester tools extension. Unfortunately, this trick doesn't help with all extensions. The Google Toolbar, for example, works only partially.
Also, because of how I connect to the internet I must turn off network-manager. This causes FF3 to start in offline mode.
I also noticed that for some reason web pages started to scroll down very slow.
As of now the problem outweigh the improvement in FF3... It is still in beta, so this is acceptable I guess.
Gnome-Do
This one is a nice little application. In Hardy you can install it by simply typing "sudo aptitude install gnome-do gnome-do-plugins" without the quotes. This application is a Linux version for Quicksilver - it can be called an application launcher but it is more than this. You can read more about it at Tombuntu - GNOME Do - Much More Than an Application Launcher.
Kiba-dock
I started to use kiba-dock a few months ago, and I like it. The version I had installed stopped working after the upgrade. The only way to get a newer version is building from source. I downloaded the latests svn, compiled it and it worked. Well almost worked. One of the main features of kiba-dock is akamaru engine - it lets launchers interact with each other. This is what makes this dock unique. For some reason it still doesn't work. I think I somehow manage to do a mistake while compiling the code, or perhaps I don't have a package required for it to work?
Update: For more information about this you can also read my post Installing Kiba-Dock in Ubuntu Hardy.

General impression
I feel that this release didn't add a lot. There are a lot of changes, but most of them are internal. I don't feel dissapointed - I knew that the plan for this release was to create a more stable system and not to add new features.
Overall, ubuntu is a very good system, especially for those who know how to and want to use their computer for anything more advanced than checking email. This release is a step in the right direction - the system is more easy to use now and (should be) even more stable.
I do not recomend to upgrade to Hardy now because it is still in beta, but it is not an upgarde to skip.
Update: If you liked this post, you may also want to read my thoughts about Ubuntu Hardy Gui.