I did just move into a new house, but basements are almost unheard of in the south. I think it is a frost line issue. Up north the frost line is about 4' down, and building codes require that the footings for the house go 12 - 14" below the frost lines to prevent frost heaving. If you are already down 5' you might as well go down 8' and put in the basement.
Here in the Memphis area the frost line is about 1" so it is pretty expensive to put in a basement. Houses here are all built on concrete slabs.