And frankly, I'm glad I don't. And I doubt that 90% of the people who say they do, really do. One of these days I'm going to dream up a way to do a test and get a definitive answer. Like people who claim they can hear the difference between

- vinyl and a good digital rip of the same vinyl
- lossless digital audio and a high bitrate (e.g. 320) .mp3
- a 320 and a 192 mp3

I tend to think they have convinced themselves of things they can't actually hear. Vinyl purists who say they can hear the gaps between samples on a CD... give me a break. (Yet they'll buy records of modern albums that were almost certainly sourced from digital master files, and happily play them & say they sound awesome. Go figure.)

Maybe it's just my shitty ears or my shitty headphones/stereo, but when you divorce these things from their various contexts, I don't hear much of a difference as long as they're coming out of the same set of speakers. I still mostly buy CDs (and some records) because I like liner notes and art - the whole experience of an album rather than just the sounds of it - and I like having the best quality backup of all my music sitting ready at hand in case my hard drive dies. But I do have a pretty large pile of mp3s from Amazon and emusic, and they sound like music to me.