Highly recommend Typhoon Lagoon or Blizzard Beach. My kids love them. You have the water, without the shark, alligator, pollution worries.
Arrive early, when they open in the morning, lines for slides will be minimal. Both have nice sandy areas with lounge chairs, lots of water activities for the kids, wave pool at TL, bobbing pool at BB, relaxing lazy river rides at both.
My sister lives at the beach, so we have done both numerous times. Water parks are by far our favorite. Also, if you worry about sunburn, don't spend more than about 3 hours at the beach, even with sunscreen. TL is very shaded and easy to stay out of the sun. BB is a little more open, but it is still possible to get out of the sun. When you are at a Florida beach you are in the sun, unless you bring big umbrellas!
So for fun in the sun, sand for the kids to play in, and clean safe waves I recommend both Disney water parks.