What About MP3?

In my limited experience (two weeks) with MP3 and AAC encoding I don't believe that even 320kbps recordings are the equivalent of redbook digital. There's a definite flattening of the soundstage and a loss of texture to the sound. There's also a sense of added grain. For non-serious listening (car or background) these are not particularly big issues.

Depending on the type of music you listen to you might not be able to tell the difference. Most rap, commercial country and any other types of overly loud, heavily processed music is so dynamically compressed that you would be hard pressed to tell the difference between redbook and high rate compressed formats. As such, I agree with Bomarc.