The truth about MP3
It's not that simple
I use MP3 to transfer my original music demos to and from my musical friend Heath. I've found it fantastically useful in that regard, as well as making compilations to listen to on my computer while surfing. There is nothing like having every Faith No More song on your computer and hitting random.
r3mix.net: the truth about mp3, is a very informative page explaining the different mp3 codecs, which sounds best (LAME), which is worse (Xing) and why. It's a page I've been trying to find for a while and it's useful for anyone using MP3 for any reason.