Give Me Vinyl Let's face it, most MP3's sound like crap. This article provides a few more details.

Here is a nice quote, "But the music contained in these computer files represents less than 10 percent of the original music on the CDs. In its journey from CD to MP3 player, the music has been compressed by eliminating data that computer analysis deems redundant, squeezed down until it fits through the Internet pipeline. When even the full files on the CDs contain less than half the information stored to studio hard drives during recording, these compressed MP3s represent a minuscule fraction of the actual recording. For purists, it's the Dark Ages of recorded sound."

I would like to add that the quality of your speakes/headphones will affect what your ears actually hear. Cheap transducers will not accurately reproduce the recorded sound.