A beach in Florida, Caladesi Island, is #1, according to the new ratings from "Dr. Beach". Number 2 is Hanalei Beach on Kaua'i. Hamoa Beach on Mau'i came in at #7.
http://www.cnn.com/2008/TRAVEL/05/22/best.beaches.ap/
I took this picture of Hanalei Beach on Lei Day in 2003.