Well besides the fact that music is a bit subjective, 128 isn't that great. It will sounds decent on an ipod or through a "standard" stereo. I'm becoming much more of an audiophile than i was before. I played around with different bitrates when ripping CDs. I ripped in a few formats 128, 192, 256 and 320 AAC. Then went even further and burned them back to a cdr. so i essentially had 6 version of several different songs. I then took them to my car since that stereo happens to be much better than my home stereo, (eclipse deck, Boston acoustics pro series speakers and arc audio amps for those of you who are curious) and basically played with each. My opinion for all bitrates covers the AAC file..and Cd burned from it. In my opinion 128 was crap, 192 really was crap too, but more livable With both of those there is a huge loss in sound, highs lows and mids suffer, but really it's fine for cramming music into a shuffle when you're working out. 256 was definitely much better a fair amount of vitality is restored. If you have the room though definitely go with 320 AAC. I'll never use anything less than that again. Basically i would say minimum requirement 192 because it maintains "enough life" and is still pretty small; recommended requirement of 256+. But this is just my humble opinon.