So, I've programmed the fourth button of my mouse to be a simple option-click (I use USB Overdrive). Now I have a gigantic button (the entire desktop) that I can click on whenever I want to hide my current app (Fitts's Law here we come!). Obvious? Yes, but the extra step of setting up a mouse button brings a whole new life to this simple shortcut.
[Editor's note: I'm using this simple but effective tip as a reminder that you can save a ton of time and keystrokes with a multi-button mouse. I use option-click on the right side button, and (the real time saver for me) command-option-click on the left side button. So with a simple thumb-press on a given application, all other applications hide on switch. You can effectively get this same behavior with third-party programs, but they are an 'all or nothing' proposition - you either always hide on switch or you don't. With the multi-button mouse, my main button still behaves as normal, and the extra buttons provide two additional switching modes. I realize the Mac was originally sold on the concept of a one-button mouse, but if you haven't tried a multi-button mouse, you may wish to do so ... there are many advantages!]

