Here's what I see around campus:
Tons and tons and tons of Sony streetstyles, clip-ons and iBuds
Sony eggos on the DJs
Occassional Bose triports amongst the pretentious rich kids
Koss UR-20/UR-15/UR-29 sealed cans and Audio-Technica ATH-P1 at the college media studio
Sony MDR V150/V250/etc for those doing audio editing or production work
Some shure, etymotic, and sony mdr-ex81 in-ear phones among the international students, particularly from east Asia.
Quite a few people with Sennheiser HD 457/477 or 212 or 202 or PX 100 - these are the ones who come closest to being audiophiles, and are actually serious about music.
I've given up on wearing headphones outside. The Etys are too isolating and therefore dangerous, my HD-497 looks weird, and I would never take my HD-600 outside. Now waiting for Amazon to ship me some Koss KSC-75s, maybe that'll be my solution for outside headphones.