Songbird? Never heard of it, but I'm always in to try new software. I'll check it out and post feedback
EDIT - Well, it didn't take much time, but...
Songbird seems like a good player on first glance. The interface is a bit dynamic, sleek and clean, but also a bit rough around the edges and harsh to fonts. The Options menu is exactly like Firefox, it even supports add-ons the same way Firefox does. I don't want to describe the default add-ons recommended by the setup as they're already explained on the Songbird website. But one of the cool add-ons is last.fm, which displays information about the artist you're currently listening to: artist info, reviews, news, photos, videos. It's an improvement over the classis last.fm interface which you manually have to download from the website and install, then install the plug-in called "scrobbler" for the specific media player you use... So if you don't have a last.fm account, you don't need one to view the information, but if you want to fully use this feature, you can open an account right from the player. The left sidebar is very similar to Windows Media Player, but the Media Library itself reminds me of Winamp's way of sorting files. Songbird also supports importing your iTunes music library, so this player seems to strive to unite all the best features of the more popular media players, which is a nice surprise.
If you have a carefully organized music library, then Songbird is NOT for you. When flipping through albums in the library everything looks okay, but going into the Metadata editor reveals that the player does not retrieve album art from the song files (even if you thumbnailed them) as well as some other information that should be there. Seems to me like it just lets last.fm take care of that instead looking for information you already entered yourself.
Second, forget about install&play. I never managed to play an AAC/M4A file in Songbird because it requires a standalone installation of QuickTime, which is c*ap compared to the awesome MP4 encoder/decoder in Winamp, which I have been using for quite a while to both rip CDs and play them without a problem. Furthermore, if you're the type that likes to setup the sound just the way you like it, you'll have a hard time setting up the Equalizer as it seems that there aren't any presets. Also, there seems to be no support for music CDs.
But Songbird is very customizable and with a bit of effort you can set it up and easily use it as the default media player. For now, Songbird is like the early beta version of a great media player we can expect in the future.