Ubuntu 9.04 comes with GNOME 2.26. However, there is another very good alternative to GNOME 2.26 which is KDE 4.2. While I would have never recommended KDE before, KDE has really improved a lot with version 4.2. So, this is worth giving a try. More here

In this article we look into the various steps in shifting from a GNOME environment to a KDE one from a beginner’s perspective.

1: Installing KDE

The current Kde version in Kubuntu 9.04 is 4.2. However, the latest is Kde 4.3. This will install Kde 4.2. if you would like to have Kde 4.3 instead, follow the instructions in step 6 and continue from step 2.