You might already know about [Windows key]+[left arrow] and [Windows key]+[right arrow] in Windows 7 to make a window fit exactly half the screen on the left and right sides respectively.
You might also know about [Windows key]+[up arrow] to maximize a window and [Windows key]+[down arrow] to restore and then minimize a window on successive key presses.
But did you know that if you have your desktop spanned across two monitors, you can easily move windows between them using [Windows key]+[shift]+[left arrow] and [Windows key]+[shift]+[right arrow]?
No more dragging windows across your desktop to move them from one monitor to the next. All it takes is a simple hotkey to get you to windows management nirvana.
A full list of keyboard shortcuts in Windows 7 can be found here.