quicksilver!
No, not the recent Stephenson novel, but this free gadget for Mac OS X users. Allows you to use the keyboard to launch applications and do much more – Dan Dickinson’s tutorial is excellent for discovering most of its features. I like this app much better than LaunchBar, which isn’t bad but got to be kind of a nuisance. Quicksilver is just… slick. And with a gorgeous interface to boot.