Well, a MP3, even at CBR 320kbps will lose quality, as it is not a lossless format. For my own ears 256kbps CBR sounds just as good as the original CD. However it is just down to opinion, many people can't tell the difference between 128kbps MP3 and a CD. There is no such thing as "CD quality" in a lossless format, I think it was in Windows Media Player 8 that Microsoft decided to declare 64kbps WMA "CD Quality", it sounded awful, hollow, and nowhere near CD quality. I think since they claim 128kbps is "CD Quality", but to me I can still hear a difference. I am sure that this thread will just have a lot of replies saying what people think sounds good to them, but in reality, it is down to you, do some tests, see if you can spot the difference yourself.