I commuted from Texas to FLL last year, and I found that there is no best hub to use for FLL. If you haven't yet, consider this: don't think of your commute as a commute to FLL, think of it as a commute to south Florida. I ended up at MIA, and PBI on numerous occasions. MIA to FLL is a $24 ride on the super shuttle. If you happen to get in early enough in the evening, you can ride the Tri-Rail train between all three airports for around $5. I was limited out of TX, but if I was coming from the midwest, I would probably use the hub that had the most flights into Florida in general. It's only a four hour drive to FLL from MCO, and slightly more from TPA. Also, it's just over two hours from RSW. As much as I hate ATL, I would guess that there are probably eight flights an hour into southern FL from Atlanta, and AirTran is a real good airline to jumpseat on.
Good Luck.
8N