What's a good family beach in Florida?

We're planning a family getaway in June, and there will be 4 adults +18, one 16 year old, and two ~5 year olds. We want something on the gulf, and when I mean on the gulf, I mean ON THE GULF. I don't want to walk across the street to get to the beach, I want a hotel on the beach, or with a room view of the gulf. We're looking at Destin, FL & St. Petersburg right now, but we want a family friendly beach with plenty of activities around to keep us busy. We originally were going to go to Siesta Key, but they don't have anything ON the gulf. I'd love to hear your experiences and advice! Thank you very much.