Ever since discovering the Amazon MP3 store a few weeks ago, I have started to wonder about audio quality between different formats available. Doing a Wikipedia search didn't make anything clearer. What is the best way to get high-quality sound? Yesterday, I could've sworn that my ears told me some 256kbps MP3s had much higher quality, but it's so hard to tell from a set of standard iPhone earbuds. Most of my music is in 128kbps quality, so it is quite difficult to know. Most of the iTunes music is in 128kbps, which stinks when Amazon sells about everything at 256kbps without DRM (what gives, record companies?). I also want to know opinions on AAC vs. MP3. Shoot, throw MP4 audio in there as well. I have pretty good ears (did the marching band thing) so I can "appreciate" the better quality. I just don't know the ins and outs of all the digital formats and I hope there are a few geniuses on here to sort a bit of it out.