This June, Joshua Katz of NC State put together some beautiful dialect maps of the United States based on data from the 2003 Harvard Dialect Survey, revealing, among other fun facts, that Eastern Wisconsin and Rhode Island are the only places that mispronounce "water fountains" as "bubblers":
In the video at the top, The Atlantic surveys the local dialects of America, calling up native speakers from across the country and matching their pronunciations of various words to Katz's maps. The results are totally charming, you should give it a listen.
[The Atlantic, via Kottke]