According to National geographic, Seychelles has one of the most beautiful beaches of the world. The pale pink sands of Anse Source d'Argent on the island of La Digue top their list of beautiful beaches. Other best beaches are found in Maldives and Bora Bora, Tahiti. You can read more at http://travel.nationalgeographic.com/travel/top-10/beaches/.
Well I live on the east coast so I only know east coast beaches and I think by far that Myrtle Beach, South Carolina is the best beach. Then it's Virginia Beach, Virginia. It's best to go during 4th of July time because they pop fireworks along the shore and it's really pretty.