Taking the Train
It's not a complicated one, but I like Good Magazine's summary of the biggest train systems in the world (top 5 U.S. cities and top 5 foreign cities). The silhouettes represent the daily rides in the city, and the length of the train shows how many miles that system covers. To the right is a quick map of each city's subway system and some statistics about their subway system.
Thanks Li, for sending in the link!