The Beryl Project is a community run branch of Novell’s Compiz, which I have used extensively. Beryl has eschewed such things as stability for the way more fun WOW factor that makes people really want to try it out. The current development is still really stable for me, both on Intel and NVIDIA graphics hardware, and the performance is top notch. I’m running on Ubuntu with custom packages built nightly, but the packages available from the Beryl Project website work great. I think they’re about due for a release soon, so if you’re looking to try something new and exciting on your Linux desktop, get ready for an experience like no other with Beryl. Under Ubuntu 6.10 I had no difficulty installing at all following the advice from their Wiki. You can also get support for Beryl under Ubuntu in the #ubuntu-xgl channel on irc.freenode.net. Give it a try, and if you like it, consider donating. The entire Linux community will thank you!