MediaMonkey is the music organizer for the serious collector.

Manage a music library consisting of small to very large collections (50,000+) of audio files and playlists, whether they're located on your hard drive, CDs, or a network. Organize, browse, or search music by Genre, Artist, Year, Rating, etc., and never waste your time trying to find mp3s you know you have. Automatically identify tracks that are missing information, whose tags are not synchronized, or that are duplicated elsewhere.

Features:

Organize music and edit tags in your audio library with a powerful, intuitive interface

Automatically lookup and tag Album Art and other metadata

Manage 50,000+ files in your music collection without bogging down

Play MP3s and other audio formats, and never again worry about varying volume

Record CDs into OGG, MP3, and WMA files

Convert MP3s, OGG, and WMA files into other formats with the Audio Converter

Create playlists and music mixes quickly and easily to suit any occasion

Synchronize with iPods and portable MP3 players effortlessly

Plus much more...

There is a pro version available for $19.95 that adds features such as:

File Monitor (automatically updates library)

Advanced Searches and AutoPlaylists

Advanced Portable Device Synchronization

Unlimited MP3 encoding

Virtual CD

Filters

Previews

Sleep Timer