Thanks everyone for your replies.
I think that for "Fine Art Portraiture", the best choice may be somewhere in the South. As you may extrapolate, I am contemplating a move. Right now, it is down to Hilton Head vs. Charleston. I leave for a 10 day trip next Sunday to explore and house hunt with my wife. We have high hopes.
It seems that for gallery work, Tim is correct - live where you like. For portraiture however, it is clear that where you live can be an advantage.