A Physicist named Dirk Brockmann used the money tracking site Where's George? to determine how far money travels in order to get a better sense of geographic regions within the United States. Brockman came up with the map above. The stronger the color blue line the stronger the division.
Then there is this map from Xiaoji Chen from MIT's Senseable City Lab that tracks phone calls between states using anonymous AT&T data.
Though close together, I can proudly claim to have lived in distinct regions according to both maps (two in the money one and three according to the phone one). I'd love to see something international, especially phone calls from migrants and diaspora back home.
Read much more about it over at NPR.