You all might have seen cool demo's of switching between active windows using a 3D stack of windows using the Aero desktop.
So I installed Vista, only to find out that Alt-Tab still did do 2D switching, although it now snows “live“ screenshots, that are also updated while you are in the alt-tab switching Window.
At first I thought that it was a cool feature that just got cut, but after some searching, I found out here that you need another key combination to get the Flip 3D behaviour.
Instead of Alt-Tab, you need to use Windows Key + Tab. Aha!
Seeing that 3D card doing useful work outside of games sure makes me happy :-))