Some years ago I began using Quicksilver to launch applications on my Mac. It turned out, it could do so much more. I still use it today.
Now Google’s come out with their version. I certainly like the QS interface better…
If you haven’t used QS, I can recommend this type of launcher, no matter which one you choose. Being able to control at least 50% of your computer with some simple keyboard-entered commands after hitting “Command Space” is addictive, if not damn productive.

OK, not a good start. (It chose to launch the Windows version of iTunes in lieu of the Mac one… tsk, tsk…)