If you want to play around with Linux (or get an install an up and running quickly) then you can't go past Kororaa (http://kororaa.org/) – Just download the iso, burn a bootable image, boot from the cd and away you go! This guy comes prepacked with all the stuff for Xgl and "just works" straight out of the box – check out the screenshots if you havent seen xgl running – this is very cool! The linux system you have always wanted 
Bascially its a prepacked gentoo install (with xgl) just to get you up and running really quickly.
The part I liked most is that I could have a play with xgl without prep'ing my machine and then spending a week downloading packages and trying to get it all setup – it just worked I run an ATI 9800 and it had no problems – came up first time – all the effects worked! Ye-yah! The only issue I found (which they already had logged in the known issues) was that the terminal doesnt work under gnome with an ATI card (how an issue like that comes about I dont know!) but in KDE it was away I'm thinking this is cool enough to do a full install which also is just a click away If you are thinking that you wouldn't mind checking out xgl then this is definitelly the way to go
Top marks to the Kororaa team – this is awesome! 
