I live in NY now, in Westchester. I know what you mean about the difference between small towns and major cities. But the small towns up here are still different from the small towns I know from Virginia. I lived in Williamsburg for three years, and Blacksburg for a total of eight and a half years. Both times, I did think of myself as living in the South.
The difference between the DC area and all of the other cities in the South is that the DC area was actually the dividing line between the Union and the Confederacy.
NY is different from VA, that's true. But I think part of that is that you're never that far from a seriously major metro (even upstate). Have you been to Maine?
Given the distant and not-so-distant history of the South, my personal experience is that attitudes are different there than elsewhere. But, of course, that's anecdote, not data.
The difference between the DC area and all of the other cities in the South is that the DC area was actually the dividing line between the Union and the Confederacy.