Ubuntu Linux 6.06 "Dapper Drake" is out and available for download.
I use Linux a fair bit these days; basically whenever I can't use a Mac and can get away with not using Windows (which is a surprising amount of the time). As a result I use quite a few different distributions, but if you're interested in getting started with Linux (and especially if you want to run Linux on a laptop), then I would suggest Ubuntu is a great place to begin.
Now that the sensible comments are out of the way, let's get all excited, because if you have some relatively spanky hardware to hand to run Linux on (I don't), then apparently Xgl and Compiz can be persuaded to run on Ubuntu Dapper. Why do you care? Well, as a discerning geek, you can now get your Linux machine to do desktop rendering in the graphics hardware which means that all kinds of OS X type GUI goodness is now possible. Check out the videos at YouTube and from Novell.
If they get this stuff working so that non-techies can install it, and Linux continues to get more friendly (Ubuntu is not bad already) then seriously, why would you want to use Windows any more? I really do think Windows will start losing market share in the coming years - we'll be using Vista for gaming and for corporate environments, but those are the only areas that it will still have strengths over free alternatives. Good times :)