Today, Alfred app version 1.0 has been released on the Mac App Store (it's actually been available to download from their website for a couple of days).
I love Alfred. I've never been a fan of Quicksilver or LaunchBar, always preferring the simpler Spotlight but Alfred seriously got me!
Also, if you feel like you want to give some money to the developers, make sure you check Alfred Powerpack. Plenty of awesome additions.