Nothing scientific, but I just left Nashville, and as much as I hate country music, I just love that area...And crazy low cost of living--I actually spent some time looking on Zillow and seeing gorgeous, new(er) construction 2000+ square foot homes for $250,000.

I was surprised at UA's ops there, including now a daily SFO flight. Service to all hubs save LAX. Much more mainline than there used to be, and pretty darned centrally located for the entire USA. The airport itself is centrally located inside the city, which is very convenient. The airport is simultaneously big and small at the same time--arriving an hour prior to departure is never an issue.