Minimize and Hide All Windows in Mac OS X with Command+Option+H+M

By combining the Hide All shortcut with the minimize keyboard shortcut in Mac OS X Lion, you can use a third ‘Minimize and Hide All’ shortcut by hitting the Command+Option+H+M keys.
As the title suggests, this keyboard shortcut will hide all other applications and windows, in addition to minimizing the currently active application or window, effectively clearing the entire screen and giving you a blank view of the desktop. If you have Dock icon translucency enabled as shown in the screenshot, the hidden apps will appear as translucent while the minimized windows from the foremost app will be in the Dock separately.
Heads up to @sambrowne for the tip.

Nice little trick
Or if you’ve been using Windows for the past 15 years it’s Win-D
Maybe you’re new, or perhaps just stupid. I’ll clue you in on a little secret. We don’t give a rats @ss what Windows users can do, or for how long they’ve been able to do it.
[...] Via | OSXDaily [...]
I’ve been trying to do this for ages! Thanks!
Somebody finally figured out how to Show Desktop correctly:
http://www.everydaysoftware.net/showdesktop/index.html
It appears that this will not work unless you have single-app mode enabled (Dock icon translucency). Without it, the hotkey will hide all except the top window.
Thanks for the great tip though, it’s very useful with translucency enabled.
In 10.7.x (don’t know about previous versions of OS X), an EASY way to toggle back and forth between a blank desktop & your current open windows is by pressing ⌘F3.
[...] works anywhere with the currently active window. You can modify it by adding an Option+H as well to minimize and hide everything including the currently active window with [...]