My commute is an hour and a half on a train, plus a half-hour to an hour walk. I never listen to anything while I'm walking - aside from the fact that I just like the atmosphere and the sounds of being out in the city, I also don't really need to be distracted when buses and taxis are constantly trying to kill me. So that leaves the train, on which I probably listen to music one day a week. I'm a pretty minimalist sort of person, and don't really want too much space wasted in my tiny bag for music. So, it's just my phone, and a pair of IEMs. I'm not a huge fan of isolation, but I do occasionally want to improve my chances of ignoring someone's racist tirade or bizarre sales pitch, all the while being able to hear announcements so I'm not completely clueless as to what the train just hit and how many hours it's going to set me back. I know this isn't the Headphone Sightings thread, but my informal observation of DC area commuter train riders is that they primarily listen on the earbuds that came with their phone, followed by a variety of IEMs, followed by Beats, followed by Bose, followed by PortaPros.
Oh, awesome. My commute will be similar (but shorter) as we're moving to DC as well. Maybe my sportapros won't look so out of place in the meantime ;-)