The prettiest beach in Florida is Clearwater Beach over on the gulf coast. Clearwater Beach is the only beach which can truly rival the Gulf Islands National Seashore which include Santa Rosa Beach, Destin, Panama City Beach, and Pensacola Beach. I could also mention Grayton Beach State Park for the more nuanced beach lovers.
Clearwater Beach is 30 minutes from the Tampa International Airport and around a 2 hour drive from most of Orlando depending on travel time. This is why many will travel to the east coast beaches in Florida on the Atlantic Ocean side.
Both Clearwater Beach and Cocoa Beach are great beaches and they are both on a barrier island. You will probably find more nature trails and sand dunes around Clearwater Beach as typically a gulf coast beach will be more tourist friendly and will also have a fishing pier.
Honeymoon Island State Park and St Pete beaches in Florida are two amazing locations within 30 minutes. These beautiful beaches are unique and family friendly. You will find the same soft sand everywhere along Florida's Gulf Coast that you will find in Palm Beach County to the north. In the sunshine state you have overrated places like the Florida Keys beaches, Key West, Daytona Beach, Fort Lauderdale and Miami Beach and then you have the beach destinations visitors return to for a lifetime like Clearwater Beach.
Marco Island, Sanibel Island, Amelia Island, St Augustine Beach (awesome), and Siesta Key Beach. If you prefer a secluded island paradise some are listed above. A barrier island location is just about the same thing. Just be prepared to pay a little more for supplies at secluded beaches.