i think 320 is overkill.. I cant tell the different after 192 which is my perferred rate. 128 is actually fine for a lot of tunes, but at 192, even the most complex melodies and bass patterns retain their characteristics to the trained ear.

Yeah that's what I think, too...
Although I use :
lame -k -q0 -v --vbr-new -V0 -b192 -B320 -F -ms

This allows lame to
keep all frequencies,
using highest quality,
using new vbr routine,
with (highest) vbr quality "0",
with a minimum bitrate of 192,
with a max bitrate of 320,
forced 192 bitrate on silent blocks
and true 2 channel stereo mode.

These arguments give me mp3's that are *slightly* larger than fixed rate 192's + 15-20% max.
But I think these are definately worth it.
Especially since mp3's encoded at fixed bitrate of 224 with none of the above mentioned arguments are just about *exactly* the same size.

I especially like the VBR bit (no pun intended) because while most of the song is encoded at 192, it uses 224,256 and 320 for when it comes accross the more complex parts of the song that need a little extra love.