Testing it now, I just imported my iTunes library. In my opinion, a bit of an iTunes rip off. It has a dark interface, which is a bit of a turn off. Also, no gapless playback on this. It's a good alternative if you don't like iTunes and includes a nice integrated browser which allows you to download songs right into your library.
Edit: Sorry, this should be in the Cross Platform section. Songbird is available for Windows, Linux and Mac OS X.
I think the idea is pretty cool, however i agree with you about the interface.
Songbird supports skins known as 'feathers'. There is a light one included (at least there should be) called 'Dove'. Sort of an inverse of the default theme.
At the moment, it's only a proof-of-concept. They even say that it's not ready for full-time use. But they are constantly working on it and it should be a great alternative for the IMO bloated iTunes (why
include iPod features if you don't have an iPod?).
It's a pretty slick program that I will be keeping an eye on. Noticed a few bugs when I used it, RC2. Crashed on me a few times but that's to be expected with a beta program.
Great... just a couple of days back I was wondering... whatever happened to that app called songbird !! 
Hey iTunes, you're looking kinda ugly.
I tested RC2 on Linux a while ago... didn't really like it.
I rather use Banshee on Linux and iTunes on Windows 
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