Alfred App
alfredapp.com
alfredapp.com
EDIT: It also doesn't seem to have a built-in calculator. :(
The design is great. It's a bummer that Quicksilver development has ceased. Google QSB is cool, but it's also nice to see a free/ISV competitor pop up with a genuinely capable product.
I'll keep tuned for updates. It does seems promising, although it isn't yet complete enough for me (or for people who tend to use Quicksilver as more than just an application launcher).
EDIT: I just noticed Alfred uses very little memory (12.5MB after launching an app). http://grab.by/2V19
My point was how little memory Alfred uses when compared the Quicksilver or Google QSB (the latter currently taking up 39MB at the moment).
[I just noticed this reply was an example of this: http://xkcd.com/386/]
It is a matter of perspective, not correctness.
I currently use LaunchBar on the Mac (excellent) and Launchy on the PC (good but not brilliant). LaunchBar fits my needs perfectly so I can't see any reason to move away from it (kind of like how I wouldn't buy any other MP3 player apart from an iPod).
Wondering why this isn't open source thought. The FAQ doesn't really say, but it does indicate they don't plan on selling it at any point.
Also, opened source probably would get in the way of something so early in its development cycle.
Also Large Type, which I think is really useful to people who need to project something quickly and without record. :)