MusicBee is a freeware app geared toward managing music collections. It is easy to use and includes a comprehensive list of features. Available as a portable app here.
This audio player makes it easy to organize, find, and play music files on your computer, portable devices, and the web.
MusicBee features the ability to organize music files and edit tags in your library with a powerful and easy-to-use interface. Manage your music as a library, as playlists, or as folders on the file system. Organize, browse, and find music on your computer, on portable devices, and the web. Small or large collections are handled with ease. You can set it to have folders watched for new tracks and added to your library, with the option to tag the files from an Inbox beforehand and manage and download Podcast subscriptions and listen to your favorite radio, including Shoutcast Jamendo and Last.fm stations.
Additionally, MusicBee can automatically look up Album Art, Lyrics and tag other metadata from the web. Have a track identified using its digital sound signature. It can also tag music easily, with many tags available for editing and custom tags that can be configured to edit other less common tags.