my 2¢:
been through two sets of the Brookstone/Maxell/Noisebuster -- first pair had amazing performence, the second pair lousy. both pairs so flimsy they broke.
tried Sony NC-11's (ear bud). almost without effect.
now have Sony NC-20's. works OK, but not great.
others swear by the Bose. they work, but overpriced.
do a ft search (travel tech forum). this topic has been covered many times.