I only recently found out about Compiz and XGL ( http://www.novell.com/linux/xglrelease/ ), some projects Novell have been working on since 2004.
It's essentially a 3D accelerated desktop for Linux and has been submitted to X.org for inclusion in future Linux Desktop releases.

Make sure you check out videos on the link above but more importantly, make sure you look at the Compiz on XGL video as well from http://www.freedesktop.org/~davidr/xgl-demo1.xvid.avi ( May require an extra decodec )

Interesting times ahead for both game and desktop developers.
How do you think it will stack up against Vista?