Hmm it sounds interesting. The best sounding part for me is the automatic looking up the Wiki articles on artists.
You said you've been looking for a replacement for iTunes -- what about iTunes turned you off out of curiosity? And does Songbird fix what you don't like about iTunes?
The only thing holding me back from going into this Songbird is because of the things I like about iTunes. I like the sharing of songs, I like the way playlists and smart playlists are done and can also be shared, I like the rankings, and I like the overall simplicity with usability. I also started using an alarm clock in conjunction with iTunes. (Hmm I guess I like quite a few things...

) You said Songbird syncs with iPods, so does it also have these iTunes functionalities?
What I don't like about iTunes is that it seems to hog a lot of my memory and CPU time. Also, I'd like for this Wiki thing.