Ubuntu 9.04 came out on Friday .. I upgraded my laptop (Dell D820) to that yesterday and did a total restructuring of the machine. I also put back a (small) Windows partition .. I've been bitten enough times without being able to present that I had to do it!
So far excellent experience with Jaunty Jackalope! I had some issues with Thunderbird and the Lightening plugin (basically, it doesn't work :() but that's ok because we're in the process of moving to Google Apps .. so I took the chance to set up GMail and the Google Calendar to work offline etc..
I have to say the end-user quality of Ubuntu is amazing for a free product, no, for any product really. I think Ubuntu raises the bar that we at WSO2 and other open source manufacturers must meet or beat!