scenster or hipster
a person who exclusively identifies themself with a group of hip urbanites by doning the requisute dress, attitude and lifestyle. a person who attempts to rebel against society as a whole, and assert their individuality but only succeeds in becoming a unoriginal drone of the smaller sub-sulture and thus becoming regimented by the sub-culture's mores.
Kids everywhere who wear the "revitalized" and back-in-style trucker hat. Or the messing mod haircuts we all love to hate.