Similar to TuneUp, SongGenie (above left) creates an acoustic fingerprint of your tracks to identify them and fill in missing or incorrect metadata information. It works with most standard music file formats (MP3, M4P, MP4A, etc.) and gets its metadata information from the MusicIP database. The same company also offers CoverScout (above right), which uses the corrected metadata to find album covers. It also lets you edit and print the cover images.
SongGenie and CoverScout SongGenie: $30, CoverScout: $40; Mac only; equinux.com;