welcome to my music library nightmare

[treanglin]

If you're running windows, you may want to take a stab at the task with GoldWave. (goldwave.com)

It offers 32bit and 64bit versions and has batch conversion capabilities of single files and folders. It also has the wonderful ability to "scan" subfolders and convert the files in those folders as well.

One problem, as you've mentioned, is that you only want to convert audio files which are not already in mp3 format.

I'm not sure how attached you are to your folder hierarchy or organization model but you may find it worthy of consideration to script something to simply dump all non-mp3 audio files into one folder, do the batch conversion with that folder as the source, and then redistribute the newly converted mp3s into the proper folders of your choice. (organized by artist/name/whatever criteria. )

That's how I've done it (on considerably less data however.)

Hope this helps.