SongKong is an intelligent music tagger designed to make the task of managing, organizing, and cleaning up your digital music collection quick and easy. It's for those of us who care about music and need it properly cataloged with high-res artwork, but without much time to spend on accomplishing this. SongKong supports most audio formats, including MP3, MP4, AIFF, WAV, FLAC, Ogg, and WMA.
SongKong can identify songs and fix misspellings, add metadata such as as artist and album and album art, and rename songs based on the new metadata if you wish. SongKong uses intelligent acoustic-matching from Acoustid to listen to your songs and find matches, even when they have no information at all, but also takes advantage of existing file information to ensure you get the best album match. It can deal with large music collections as well as small ones. If you use iTunes, it can automatically update it with your modifications.
SongKong can also use Acoustids to find duplicate songs.