Alright, while waiting for the jailbreak software for my iPod touch 1st generation, I’m wasting my time by exploring the iTunes 9 which I never care to explore before.

I re-arrange all my music collection consists of .mp3 files.
Yeah, I like to keep my music files in .mp3 files as it can be playback on most of all devices even the most native mp3 player.

So I do a research on the internet on what peoples said about the best decoder and settings.

The Format

AIFF & Apple Lossless & WAV are equally the same.
No frequency were loss, you will get the exact sound as is you are hearing the songs from CD.

AAC & Mp3 are lossy type format.
Means this format discard some “unheard by human” frequencies and  less in size.
The audio quality are decreased as well.

Hence, here’s my conclusion.

AIFF & Apple Lossless & WAV > AAC > MP3

But yet I still prefer Mp3 over those other formats. ;-)

When you choose Mp3, set the settings to highest, and use normal stereo settings.