Why Washington DC Rocks
by Handsome Matt
A fairly well developed (and more importantly well used) mass transit system.
The buses are powered by natural gas. Meaning a clean fuel source that could easily be converted over to hydrogen or methane.
Bike paths. The whole city encourages walking, biking and all manner of outdoor activities.
Combine that with the East Coast Corridor, and I can get all the way up to Maine if I wanted without ever using anything but my feet and various, efficient mass transit systems.