Source: http://feeds.gawker.com/~r/lifehacker/full/~3/389666221/duplicate-cleaner-ferrets-out-file-dupes
Windows only: Hunt down multiple copies of the same file with Duplicate Cleaner, a lightweight and quick duplicate file finder. Add multiple paths to Duplicate Cleaner's search, handy for de-duping a media collection that spans multiple drives. Filter your duplicate search by file type, content, size, and date of creation. Additionally Duplicate Cleaner offers support for MP3 metadata, including artist, title, and album, a fantastic feature for weeding out a large music collection. For additional tips and tricks for cleaning up your duplicate files check out how else you can de-duplicate your data with free tools. Duplicate Cleaner is a free download for Windows only.