For those of you who have a Intel graphics card (many laptops), and are running Ubuntu and haven’t upgraded yet. Don’t upgrade until you’ve read up on the problems people have been having with hardware accelerated graphics, including Blender. Check out the thread here called Blender in Ubuntu 4.09 (spelling mistake in the subject 
). Then go over to the Ubuntu forums and search for problems with intel graphics cards and Jaunty. There are some instructions there for possible solutions, but most of them are not that simple, and some require installing a newer kernel and stuff, which may break support for other hardware (wireless network cards, newer soundcards and so on).
I’ve tried some of the safer and simpler fixes on my laptop, and while I’ve gotten improved performance in glxgears and wobbly windows working. Blender is still broken. Half the viewport doesn’t update correctly and is filled with garbage. For me it’s not a huge problem, as I mostly use my workstation with an Nvidia card for Blender, but still somewhat annoying. Apparently a lot of the intel bugs are on Ubuntus to-do list for the next milestone, so maybe it will be fixed in the not so distant future.
Note that this only applie to people with Intel graphics cards, not if you have an Nvidia or Ati one. Those run fine as far as I know.