What is a great fun vacation spot for the family?

Me and my family ( inlcuding a 2 year old ) will be going on vacation sometime after christmas, but we are undecided on where to go. We are in the South Carolina area. We live only and hour away from Myrtle Beach SC and about 3 hours from The TN Smokey Mtns, but we have been to those places several times. We was thinking about Florida, but Disney World is out the question, because we really don’t have that much money to spend, plus we have a small child, and my wife will be about 7months pregnant. What is a really great place to go to, we would like some where warm. And no more than 15hours away from South Carolina, because our small child. What are some good places at Florida, nice beaches, any dolphins? Great recenable priced hotels? What are some other good places other then Florida?