Florida's largest cities aren't that Democratic compared to other large cities. In fact, Obama didn't get 70% in any of FL's largest cities.
Err, I mean large Urban areas. See FL-17 for an example of what i mean--a district that isn't all that gerrymandered, that is one of the Safest for the Democrats in the entire country right next to 3 marginally republican ones (the Cuban ones)
Well they made it so FL-17 is like 82% minority.
Orlando is growing more democrat, Bush only lost it marginally but Obama won it by a good amount I believe.
As to large urban areas Pinellas County is a pretty good bellwether. It has conservative north and democratic (and black) south. It voted for Gore, Bush, and Obama.