How many different dialects would you say are in America?

This guy says 25, but others say more and some are more general and say less. However, even with the 24, I find so many variations in Louisiana for example that it's more than that even. For instance, there are many different variations of actual Cajun French spoken that I believe have caused differences in dialects of different areas, and then in New Orleans you have distinct differences you can detect between a person from say Chalmette and someone from say Terrytown or maybe Mid City, etc, and proceed west and there's a noticeable difference in what you find around LaPlace, Reserve, Lutcher, and then BR, or cross the river and listen to people speak from the Lafayette area and then Opelousas. Perhaps they're more subtle differences that people here pick up on more so than someone from out of state might not notice right off, but I think there are plenty more than just 25 different dialects in this country.

What say you?