I have a large collection of iTunes music, mostly from ripped CD's (almost 20,000 songs). My music files are: "MPEG audio file / MPEG-1 layer 3" @ 192kbps (I'm guessing that's same as MP3 ?). I've searched around a bit and see that most audiophiles generally agree that AAC is "better" than MP3. Question: Will an average listener (like me) notice a difference between MP3@192kbps vs AAC@256kbps? In iTunes, I see that I can "convert" my music library pretty easily from MP3@192kbps to AAC@256kbps, and was wondering if it would be worth my time to convert 20,000 files. Thanks for your input.