Interesting article from today's Washington Post. A group at MIT has compiled a series of maps showing the most efficient forms of urban transport. Not surprisingly, bicycles scored quite well (although many of the readers seem to be at pains to accept this judging by the comments).
To examine the maps in detail, and perhaps find your own city, I recommend going to the direct link here. It's pretty cool. You can click on a spot in the city and it will reconfigure the map from that starting point. Note: The maps are a little slow to load.