MusicBee manages to combine the best features from applications like iTunes, Windows Media Player or Winamp, while adding a lot of useful features that aren't available in those popular media players. For example, you can automatically fix the tags for all the songs from your music library with just a few clicks.
MusicBee has a great Last.fm integration: it automatically scrobbles the tracks you play, it lets you import your loved tracks and your playlists, it has a cool feature that imports Last.fm tags and there's also an option to sync play counts with Last.fm.
The application supports tabs and it includes a Mozilla Gecko-based browser that lets you read information about the songs you're currently listening and download songs from music blogs.
Besides the extensive support for music formats (MP3, WMA, Vorbis, AAC, FLAC), the application converts music files from one format to another and synchronizes your files with many portable devices, including iPod and iPhone.
MusicBee is probably the media player that integrates with the most popular music-related web services and the nice thing is that it's constantly improving. Steven, MusicBee's only developer, is open to feedback, sometimes implementing user suggestions and fixing bugs in less than a day after they're posted. It's amazing to see that the first version of the player has been released in December 2008.
The downside of including a lot of features is that the application might look cluttered and some features are difficult to find, but that's a small price to pay.