Hawks Cay Resort is running a special on Travel Zoo right now. I've never been, but it looks nice and they have camps for the kids and dolphin experience. A couple years ago we went to Captiva Island which had really nice beaches. It's on the gulf side. Flew into Ft. Meyers. Stayed out South Seas Island Resort which has been listed in Parenting Magazine's list of best family beach resorts. Have also been to Disney's Vero Beach. While I did not think the beach was as nice as the beach in Captiva, we had an awesome week and so much to do for the kids at the resort!