I have been a longtime paid user of LaunchBar which is a great way to keyboard your way around your Mac. Quicksilver is free and has a cleaner, more Mac-like feel to it. At first glance they seem to do pretty much the same thing. Free is good!
More new software to recommend today: If you prefer to interact with Mac OS X through an add-on utility like LaunchBar rather than the standard Dock, check out Quicksilver — a completely free, open source software launcher (and more) for… [Apple Matters]
I’ve spent a few more minutes with this now and have to say Quicksilver is very slick and actually more powerful than LaunchBar. Here’s a quick tutorial if you like as there are no screenshots available on the Blacktree site. I am just starting to cruise the forums and finding much to like…
LaunchBar (something I’ve used for all 3 years I’ve been in OS X) has just been removed from my start-up items and replaced with Quicksilver…
More on how Quicksilver works can be found at Tesugen.com