Call me a gadfly, but does anyone else find the Alt-Tab functionality in Vista to be almost useless? Almost all of my windows are text, which means that they all look very much alike when they are shrunk down. In addition, the selection rectangle as you cycle through the windows is just a faint outline with the same interior color as everything else, so it's very difficult to see the current selection. Since I routinely keep 20+ windows open, changing between windows has become very painful.
I was delighted to find that you can tell Vista to revert to the Windows XP style window cycling:
The short summary is to create a DWORD called "AltTabSettings" in \HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer and set it to 1.
This feature doesn't appear to be documented by Microsoft.