I have "better than average" hearing and I can say without a shadow of a doubt I'd prefer a 320kbps mp3(encoded on LAME) over a CD anyday. I have compressed a 320 down to 128 and noticed a HUGE difference in sound quality than compared the 128 to CD and it sounds the exact same to me.

It could just be me though, when my friend sends me songs and they are 128 I can notice the poor quality immediatly and I re-download a higher bitrate version(usually 192). When I asked him about the crappy quality he said it sounds great too him.

I also notice a huge difference between a downloaded 320 and a ripped 320 I do myself with LAME and CDEX. But like I said, my hearing is a tad bit weird.