Things that work on XP but not on Windows 2000 (SP4):
Wallpaper NEVER changes no matter how you set it up.  Switching desktops on XP and the background wallpaper switches smoothly - not on W2K.
Dragging a window replica from the current desktop to a hidden one takes the window there, but NOT the taskbar button.  Again, works fine on XP.
Other than that...  This tool makes an excellant BOSS/WIFE KEY...