This app is just so incredibly packed with features... It pretty much automates anything you need to do with music files.
Renaming based on tags, retagging based on file name/directory name, tag editor, artwork browser, etc...
From the creator:
"Media Rage can read and write information stored in MP3, AAC/MP4, FLAC, AIFF, WAVE, BWF, and Ogg Vorbis audio files. Media Rage can assist you in cataloging, organizing, sorting, and updating thousands of audio files with ease."