Using geocoded Twitter data, a linguist has put together heat maps of how and where we refer to the American man (and, not so infrequently, the American woman). I'm proud to live in a "pal" enclave.
You can play around with the interactive map over at Quartz, and read more explanation of how the maps were created. Basically, it's not just popularity—it's frequency, adjusted for population and clustered geographically. So Texas isn't necessarily using "bro" more than the rest of the country, but Texas is ground zero for a standout brodown.
Here are the "buddy" and "dude" strongholds; more at Quartz.