I'm with Sam vis a vis CD vs MP3 players; but its more about the hearing range of the listener. Lots of people -can't- tell the difference most of the time....for whatever reason (from impacted earwax to 'Wow that shotgun was loud in the shed!'), they simply don't have the dynamic range perception. Those who do though are =very= aware of how compression schemes thicken the bottom end and erode the top to where it has all the crispness of a bag of soggy potato chips. It's fun watching the faces of those who don't know better when I put a pair of Sennheiser phones on their head and they get to listen with an absolutely flat  distortion line up to 20khz. They always reach for the bass boost first, then ask where all those high end sounds come from. A new cut? A cover that sounds almost identical?

Of course all the good compressors let you choose your damage percentage, but it's gotten to be the norm to squeeze a music file as small as you can, to get more on whatever device is being used. You might be okay with the latest hip-hop, but try and do a classical piece with full orchestra like that.... (shudder)