This just in: We're not sure when this feature came about. A quick search of google revealed nothing about it.
The key binding ctrl+alt+tab is our favorite accidental discovery of late. It works much like alt+tab, except that it stays on the screen.
It's possible to actually look at the windows, move back and forth, and remove your hand from the keyboard while the windows are heads up. It can be amazingly useful when many application and windows are open on a single laptop display.