There is also a related question.

"Own it on CD, Allowed to download (or buy/rent etc) the MP3 version?"

My reply to that, is I think in this case, where you own a digital copy already, then you should be entitled to download a mp3 version of it provided that:

1. The mp3 version you end up is no better "quality" than the CD version could ever be

2. The mp3 songs are the same (or substanially the same) as the songs on the CD you already own (downloaded the extended version in mp3 while you have the "regular" version on CD is not kosher).

3. You own the copy on CD already, and you could if you wanted to/could be bothered - make a mp3 version of the CD.

This would let you obtain mp3 files for CDs you already own, legitimately from p2p sources. Of course most of us know that the p2p versions of most mp3s are crap and you can do better yourself, but its the principle I'm getting at.

The record companies like to take the position that "all mp3s are theft" which is clearly wrong.