I'm still not convinced that Vista is a net win, but it just scored some points with me. It has XMouse functionality built-in. I can't remember the last time I set up a new computer and didn't immediately download TweakUI.
By default, in order to switch windows in Windows you have to move your mouse to the window and then click in order for it to take focus and move to the top.
In Xwindows, which is the windowing system I cut my teeth on, you can (configurably) just move your mouse into the window and it takes focus and moves to the top.
All that extra clicking annoys the bejeebus out of me and irritates my RSI. So when I get a new Windows box, one of the first things I do is install TweakUI and set it up so that it behaves like Xwindows. With Vista, I didn't have to install anything-- there's an option in the control panel.