Show desktop

[beeswax]

Came across this accidentally just now. If you move your cursor to the extreme bottom right of your screen, at the end of the toolbar, a message pops up saying Show Desktop. If you keep the cursor there for a couple of seconds more any open windows will be minimised. Moving the cursor away from this area will return things as they were.

[srochford]

Right click on it to choose between "peek" (what you describe) and an immediate "show desktop"

[_Adam_]

Microsoft's Help and Support found in the Start Menu has a section for what is new in Windows 7, this and many other features are presented with videos.