I've started coloring my layers in Photoshop much more since I discovered this shortcut. Right-click on the visibility icon (eye) in the layers palette to get a menu that will let you assign label colors to the layer. It's quick and easy! "Show/Hide all other layers" is also in that contextual menu, and can also be invoked by option-clicking the eye icon.
[Editor's note: Unfortunately, I can't test this one as I have only the "Elements" version of Photoshop, and there are no color layer labels available.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20021011055614748