American Culture(s)

I recently read a book called Balthazar. It's book number two in a series called the Alexandrian Quartet -- four novels about a collection of characters who live in Alexandria. One of the central themes of the novels is that idea that the city makes the people who they are: in the first novel, Durrell (the author) goes as far as saying that it is not the characters who live but rather Alexandria that lives through them. In other words, the characters' personalities are the manifestation of the character of the city itself.
I have wondered about this a lot. To what extent is this idea real? Are we manifestations of the consciousness of our city or town? To what degree? We live in an incredibly mobil society. Most of us have lived in multiple places. In what ways are we conglomerations of the cultures that we have belonged to, or at least the cultures that have surrounded us?
On a related note, I think about the homogenization of America a lot. It seems to me that we are becoming less regional, in terms of cultural distinctions. We watch the same movies and TV shows; we shop at the same stores; eat at the same restaurants; listen to the same music; wear the same clothes. As we move around, our regional cultures blend. What have we lost in terms of regional character? What have we held onto? What have we gained?
I'll close this with the words of Jack Kerouac: "Whither goest thou, America, in thy shiny car in the night?"