Sony? hmmm...
256Kbps is always better than 128kpbs for sure unless the encoder have bugs

And i think 256k is "too much" for normal user, unless you are audiophine or you have golden ears.
128kbps is already good enough if the encoder is Nero AAC encoder or iTunes AAC encoder.
Read this: http://wiki.hydrogenaudio.org/index.php?title=AAC_FAQ

128k is enough imho. IF you found out the 128k encoding produce audio artifacts just go 192k.
OR you are using high end earphone which you could tell the quality difference between 128k and 256k.

Does the phone comes with software that allow you to convert the audio to FLAC? And FLAC is more overkill than 256kbps lol
Cant help much since im still using the ancient w610i

FLAC is audio archiver, you can call it "ZIP for Audio". most ppl use FLAC or other lossless format are for backup thier audio CD.
if the CD damaged so ppl could use it to restore the audio back to other CD.
Or audiophile use FLAC to listen on thier high end audio equipment.

No point to use FLAC if you are always listening audio on other noisy environment.
Just my humble opinion, AAC 160kbps or 192kbps are already "near-transparent"(NERO aac encoder and iTunes ONLY), plus their filesize is much smaller than FLAC which are usually 15mb and above.
you can use FLAC as long as you have enough space on your memory card

Noise canceling headphones MAY reduce audio quality, or add more audio artifacts to your audio
I dont think high end headphone are equipped with ANC. i could be wrong though.

and if you tell the ppl on hydrogenaudio you could tell the difference between FLAC vs AAC, you could get banned on there if without any proof lol

Thats why if some one claims if he can tell the difference between FLAC vs AAC at specific bit rate, that ppl need to do ABX test...
http://en.wikipedia.org/wiki/Transparency_..._compression%29

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Added on June 22, 2011, 1:10 amdepend on the Encoder...
AAC 128kbps encoding have lowpass filter(16khz) enabled IIRC. while LAME 320kbps encoding does not have lowpass...
thought this will need to do ABX test to proof AAC 128kbps is better than LAME 320kbps
and will require killer samples too.

This post has been edited by 1024kbps: Jun 22 2011, 01:10 AM

MP3 has wide hardwares/software compatibility, though AAC already catch up imho, and MP3 need at least 160kbps, and VBR to sound "artifacts free" to my ears.
while AAC require less bitrate because its better than MP3 at the same bitrate.