If you have Object Desktop make sure you try out the WindowFX 3 (2.89 is the current one). We're gearing up for WindowFX 3 and it has some pretty cool stuff. It will require a good video card in order to make the most use of and right now it works a bit better on ATI cards than nVidia cards.

First thing is that it has a much cleaner interface including a wizard to guide new users through the process so that they know what it can and can't do and recognize what might be overdoing it (i.e. turning on every effect at once may not be a good idea)

We had this feature in before Windows Vista added it. Mouse over previews of what's in the taskbar.
Similarly, new alt-tab options for displaying currently running windows live.

This is probably one of my favorites - a bunch of new, subtle open and close animations that work very nicely.
We're still putting the final touches on WindowFX 3. It's very cool but it isn't for everyone as you need a decent hardware set up to make the most out of it and you need to be savvy enough to know what features you'll want to use and which ones you don't (i.e. different people will want different effects -- some people might want shadows under their windows, others might want swaying windows, others may want to mix and match).
If you don't have Object Desktop, you can get it at www.objectdesktop.com