Interesting thread. We considered moving to Florida before deciding on Hawaii.
We had a couple of big issues. (This was in 1999.)
Our biggest issue with Florida was water. In 1998-99, there was talk about problems with the aquifer, lack of fresh water, and the possibility of having to repipe in order to provide non-potable water for irrigation.
Another issue was that at the time, 80 people per day were moving to central Florida. I don't know what the current numbers are, but that's an issue.
You need to do research before you move. Several people provided good resouces. Take a look at the census numbers, as well. It'll give you an idea of what's happening in various areas of the country.