Aruba was beautiful. So were the Florida Keys.
Craven should be able to fill you in on Brazilian beaches... He used to live in Sao Paolo (I think) but I don't remember if he was a sun seeker.
Or, how about the French and/or Italian rivieras? I haven't been to either --- back in my beach seeking days I used to go to Mexico, Puerto Vallarta in the late sixties and early seventies, for example.. not the tourist extravaganza it is now. I lived in west Los Angeles and went to LA's beaches a lot. I've had my last beach derived sunburn though.
Where I live now going to the beach is usually a chilly matter, as in bundle up and bring the dog to the beach off King Salmon Road, where you can eat a great breakfast at Gil's by the Bay and then go for a walk that is just as gorgeous in its way as walks on beaches in warmer climates. But, not what you are looking for right now.
I thought Aruba was beautiful if you like flat, windy, desert islands. The Dutch architecture combined with the Caribbean colors & rhythms were very interesting. English is spoken everywhere.
The French Riviera was also rather arid in many places, but mountainous and green in others. Spectacular scenery and impossibly blue water. GREAT food and local wine. Very sophisticated compared to Caribbean or Mexico, but the beaches are rocky. You'll need to know a little French to get by.