Not to get into the "mine's better than yours" thing at all, because clearly everyone has different preferences, but I just have to post a comment here because after I read this post this morning I downloaded both Butler and Quicksilver.

I was impressed with Butler, especially the cool iTunes transition/info window that pops up, and figured as an afterthought that I'd give QS a shot.

Ten minutes later I was hooked - Quicksilver is a very impressive tool that while similar to Butler has some cool features that I appreciate. For instance, drag n' drop an item off the search window into an email. Very cool. The appearance of phone numbers and addresses is a little friendlier, and I like the easy way to select many different choices of actions to do with a result. And the author's commitment to open source/freeware - wow, it really means a lot with an app as cool as this one.

Anyway, these apps have improved many times over since I last downloaded something like this (long time ago). These won't be going into the trash anytime soon.