I just got ubuntu 9.0 installed in my laptop, my first linux experience and thought of sharing about it. Installation was a piece of cake, never thought it would be so simple to do a linux installation, credits to ubuntu community.
I seriously didn't see anything you can't do with ubuntu that you can with windows as you have every software required for development (for java :)). I just got my eclipse,ant, maven,android, google app engine & google chrome, not sure what one needs more than this for a java development. Extremely fast, no need to say yes,yes & yes & most of all no virus. I have setup all my development on ubuntu and comfortable in doing it :).