Don't convert the iTunes AAC to analog only to recapture it. Likewise don't burn a CD. Just break the DRM and convert the files to AIFF (on a Mac at least). The software is out there. I can probably get a link if you can't find it - this may help to find a Windows program if anyone needs one.

You'll still have to re-encode as MP3 so it's not going to be a lossless transcode, but it's about as good as it will get.

Bruno