When I lived in DC I commuted from Huntington to Foggy Bottom. That was roughly 40 mins, with 30 min on the train and 5 minutes on each side for getting to the train station and then from the train station to work. However, I could have rented in Foggy Bottom, 500sq/ft for $1600/mo and reduced my commute to a 5 minute walk. I guess if your willing to live in a box or a box in a basement you can reduce your commute most places.