alfred

This program is like an enhanced dmenu for Mac. Is it OSS? No, which is lame. But, from all the Mac wizards I've talked to, it's as good as it gets.
So I think it's worth spending some time to learn it, as I'm doing pretty much half of everything on Mac for school/work/video editing.

The big thing about Alfred seems to be the big focus on minimal keystrokes-to-output, which is cool because it's pretty much like a command line. I've also heard of command-k which (i think) does a similar thing.

Check out a History of the launcher for more of a primer.