Duplicate Music Files Finder
Full user review
"Worked like a charm"
I had so many MP3s and AACs with the same song on my MP3 player, it drove me nuts. Download, install on WIN7/x64, run by identifying my player driver and it's SD Card as hard drives - zip, bing, all cleaned up.
Had to de-select some duplicates manually, since they were not really duplicates, but it was a small matter to do that.
Free, and it works. If you can find something better, then you better let me know too.