I'm slightly ashamed to publicly admit this, but my design is a poor imitation of what I think is a rather good design here:
http://www.atebits.com/tweetie-mac/
I took some cues from them, simplified it so that I could actually do it myself, and then stopped improving it when it was no longer absolutely embarrassing.
The logo is just Arial. Go figure.
I have since redone it almost completely, and I think the new one is much better, but like I said, you won't be able to see it until sometime later this week/next week.
The new design is much more focused and less scattered. Each page has a clear point to get across. Aesthetically, it's nicer as well, although I've confirmed that with precisely zero people.
As far as the app itself, I just made that up from scratch.
Did you guys have any inspiration?
Did you start with a template and tweak it?
Do you have a solid design guy on your team?