Kennedy Space Centre on launch day (if you're really lucky and time it right - I've failed twice so far).
Clearwater
Everglades
Shopping, if you must, in the malls
The parks, obviously. Seaworld and Busch Gardens are my favourites. Discovery Cove if you want to go swimming (expensive, leave the camera behind). Disney didn't do much for me (Epcot was OK and I never made it to Animal Kingdom).
All three times I've been I stayed on I-Drive. The hotels vary quite a bit but I've had no complaints.
Tips for the parks:
You're just about in high season now so they're going to be busy. Plan ahead. Go early, grab a map and note the times of any shows you want to see, book stuff if you need to but bear how long that is likely to take in mind, as you won't be the only one.
Then, go straight past all the attractions at the entrance and head for the back of the park. Start with the attractions there and work back towards the entrance. This tip is oft repeated but rarely followed, so by following it you'll be ahead of the crowds and avoiding the longest queues.
Finally, it can be a long day especially when you have family to think about, but it is worth bearing in mind that some of the parks put on special shows in the evenings.