I was in a meeting a week or two ago where one of my bosses was using the Mac in our conference room and, upon realizing he had to open another app, hit Command-Space as a reflex. Nothing happened - Quicksilver wasn't installed. Those of us who use Quicksilver (about half of my group) all giggled - because we've all been there, grappling on a machine without QS installed.
For those of you who, like my boss and my coworkers, live and die by Quicksilver, there's a plugin you should definitely check out. Its name is Abracadabra, and it enables a third trigger type: mouse gestures. I got to play with this while it was in alpha, and I have to say, it's really damn slick, and a natural extension on top of QS.
Marcus Volwalker has a great tutorial to help you get started. And if you need help with triggers in general, check my last tutorial.
