Michael Tsai tells us about LaunchBar 4.3. This is one of my favorite apps. It's no longer fashionable since there are similar free products for OS X, but it never causes me a bit of trouble and it does everything I need. I even try to learn new features occasionally. I like the way they tied in Spotlight too. I'll update to 4.3 -- I also like that I've never had a problem with an update.
Also, I have a weird trait that I like paying for good software.
BTW, there's still no comparable equivalent for XP, despite hordes of would-be imitators.Update 8/1/07: Wow, what a staggering array of features! I'm going to try to learn some of them, starting with the calculator. If you hit cmd-spacebar to launch LB (Cmd-F inside LB for Spotlight), then if you type any digit the calculator starts up.
Update: Great article - how to get more out of Lauchbar.