128k you can hear the differnce, only at certain levels. Most codecs will distort the bass, WMA is known to sound "tinny" whereas MP3s are known to distort the bass.
You can definatly tell the differnce from 44100 khz uncompressed PCM to 128k compressed file, it's "Near CD Quality".
Most people cannot tell the differnce, not everyone's hearing range is equal so I shouldn't be speaking as such it really has to do with hardware. You wouldn't be able to tell the differnce if you were BLASTING the music on a dj setup, if the volume is too loud you only hear bass and distorted noise not to mention some minor hearing loss. Those levels are NOT industry standards they're to make $$$ for the club.
A $300+ surround unit or any car stero w/ min of 4 speakers will display the compression faults for trained ears. $10 computer speakers will not display the artifacts on a 128k file.