QuickSilver combined with Dock Dodger!
QuickSilver is one of the best application launcher available for Mac. What is even better is it's free. With QuickSilver, you can launch any application in a few simple keystrokes. There are also many extensions for iTunes, Mail and many other built-in Mac applications. One thing that it's really efficient at is to start a playlist from iTunes. The traditional way is to click iTunes in the Dock, wait until it launches, and finally double-click the playlist. With QuickSilver, you just hit the hot key (I chose the standard one Ctrl-Spacebar), enter the first few letters of the playlist name and hit Enter. It seems as long in the description but it's really much quicker. The results are also displayed much quicker than Spotlight. One of the only things I totally hated about QuickSilver is to have this extra software constantly running in the Dock and in the "Command-Tab" dialog. Dock Dodger is the solution to that! I activated "Launch on start up" in QuickSilver preferences and I used Dock Dodger to get rid of the Dock and the "Command-Tab" icon. The app runs in the background, but you really can't see it. It's now nearly part of the OS!