I've used Quicksilver on and off every since I started using a Mac. Upgrading to Leopard initiated my longest break from using this swiss army knife of an application. Spotlight performance had improved enough that I simply got used to using OS X's ability to launch applications and find certain documents or web pages. It wasn't until Jamie Phelps [http://www.jamiephelps.com/] started singing the praises of Quicksilver to me this past summer that I installed it once again. A couple months later…