Vista RC2 is for me at least having a coupel of issues running Aero Glass. Such as not allowing me to even select despite being comfortably above the spec and having the drivers. Apparently, Sun JDK also causes some bug with it. I assume this should also work in release vista (which is iminent), but does require you hardware is actually capable of doing the Aero Glass tricks (I believe the specs lie with 128mb VRAM and shader model 2 compliance, so radeon 9500s up.)

Fire up regedit (making precuations to back it up blah blah blah), and go to HKEY_CURRENT_USER\Software\Microsoft\Windows\DWM

Set Composition to value 1

Set CompositionPolicy to value 2

Now make a pretty bat file, and fill it with the following;

net stop uxsms

net start uxsms

Exit the registry and fire the bat, and Aero Glass should kick in. I'd reccomend keeping the bat file handy, as in my experience thus far, various things (installing photoshop for one) can kill of Glass. The registry remained correct, but the DWM service needed restarting.