LR, I disagree with you.
Yes, pretty much every city, town, and village in America has the same franchises. But culturally, it is so varied... not only from region to region, but from city to city.
I live in Toledo, which is basically a blue-collar union city. The attitude here is one of practicality, without a whole lot of tolerance for the idealism I happen to be known for... y'know, try to understand the terrorists before blowing them up, people are essentially good, etc. A perfect example of our culture here would be an experience I once had... I had shaved my head, and I was at the grocery store, and a woman approached me. She said, "I bet a lot of people stare at you here, but if you went to a big city like Chicago, nobody would give you a second glance." And she was right, at least about Toledoans' reactions (I never got to test out the big-city factor). Racially, there are definitely divisions, but I wouldn't say I know of many places where a black person or Mexican person just couldn't go...
Now, take a trip 45 minutes west to Fayette, and boy, do I ahve a story for you. I was camping with some friends, and my friend and her boyfriend needed condoms. Her boyfriend happens to be Mexican, and while she stayed and helped set up camp, he and I went on a shopping trip into town. Not only were a white girl and Mexican guy given the nastiest of glares, but we were told that condoms were not sold "around here," that we'd have to drive to another town for them... LOL.
But drive 45 minutes north to Ann Arbor, and it's pretty much a liberal paradise... I happen to enjoy all the independently owned shops and ethnic restaurants, as well as walking through the U of M campus... every now and then, the liberal protestors get on my nerves, and even moreso on my signifacantly more conservative boyfriend's nerves...
But I guess my point is that even in the midwest, known for its conservativism, and even among the homogeneous Wal-Mart's, Burger Kings, and BP's, there are significant cultural differences just from town to town, some probably accounted for by the size of the town... and some because of the racial demographics... but everywhere is not the same.
I have not travelled from region to region except on vacation, which is to say, I've never been away from the midwest long enough to immerse myself in another region's culture, but people I know who have have shared stories that indicate to me that different regions of the U.S. have very different cultures.
So while there are some things in common pretty much everywhere that might jog a memory of someplace else, I don't agree that everywhere in America is the same. As far as Florida being a state of mind... I ahve songs, tastes, smels that trigger memories... and maybe since all of your memories are in Florida, that's why you are reminded so strongly of it.
Just a thought.