Sorry to revive such an old thread, but I had to chip in on this.
I've been playing with the evaluation of OranceCD, and it's everything I've been looking for in a program like this - but with one fatal flaw.

It appears the ONLY way to add an MP3 album is by using the "scan media files" option, which doesn't let you get all the nice extra info from Amazon, etc. You can't add MP3's manually, you can't add from Amazon, then attach the MP3s, you can't change the MP3 locations if you move the files from a previously added MP3 album. Unfortunately, this basically renders this software near useless for organising MP3s in my opinion, which is a damn shame, because it's SO much better than all the others in almost every other regard.

If you could just add a little "edit media file location" option to the track options, that'd be all it would take to make this the greatest MP3 organiser ever made.