I'm into application launchers.
At work (on Windows) I use Find And Run Robot and have gotten really used to launching applications (and a lot of other neat functionality) with the keyboard. I've been missing the same thing on Gnome at home but tonight stumbled upon Gnome Do it's still fairly immature but so far I've not had any issues with it and it will launch apps, find my bookmarks, and with a few plugins will search my Tomboy notes as well as skim though my MP3 collection in Rhythmbox. Very slick!!! Installation was just a matter of adding a new repository and doing an apt-get install. The author has a blog where you can read a bit more about the project.