I've only been to Caladesi Beach once, a long time ago, but I have never forgotten it. My sister Laura and I were visiting relatives in the Clearwater area, and they mentioned we might want to go to Caladesi for a day. The beach is in a state park, and you get there by ferry. And then you can only stay four hours. The ferry ride is fun, and once you are there, you experience a pristene beach that seems far away from the city. There is only beach, nothing else.
Dr. Beach is professor at Florida International University and has compiled this list since 1991. He gave Caladesi the top slot in his survey; see what other beaches float his boat: http://www.cnn.com/2008/TRAVEL/05/22/best.beaches.ap/index.html