MediaMonkey
MediaMonkey supports all the major audio filetypes from FLAC and mp3, to WMA and even M4A (AAC) files with a plug-in, and is able to sync with all the major mp3 players including the iPod. It easily handles large music libraries, and offers the same track information as iTunes ranging from album art to play count. Missing track information can be automatically added to song ID tags and playlists are easy to set up and add songs to, with smart auto playlists available in the pro version for a small fee.
System Requirements: