The noice canceling is no-where near the quality of some of the other noise canceling headphones i have tried - even while typing this review listening through them i can still hear my keyboard chattering away and the people mumbling on the phone around me.
I would say 90% of the noice cancelation comes from your ear canal being blocked by the in-ear bud, rather than the rest of the hardware.
Otherwise the headphones are good, not as good as the sennheiser cx400's ive had in the past for sound quality but decent enough to listen to the wide variety of music i listen to (drum and bass, dubstep, metal, trance, hardcore, rap and alt. rock)
on my laptop i reduce the mid range,boost the bass output to max, and raise the treble output by a couple of points
on my ipod i find that the "latin" equalizer works pretty well, as does "small speakers"