Two Monitors and AutoHotKey
I prefer to use the keyboard whenever possible. I have a two monitor setup and found myself moving windows from one monitor to the other using the mouse. However, using AutoHotKey I was able to do this by keyboard. Also I wanted to swithc easily to a particular window using the keaboard.
Update: The functionality has now been integrated into Windows 7.
AutoHotKey is an utility for creating hot keys. Each hot key can runs a command or a small script.