There are many beautiful and famous tropical beaches, and Pacific, Caribbean, South and South-East Asian beaches are, probably, among the most appreciated, though often overrun by vacationers and tourists - or too "exclusive":
http://www.cntraveler.com/galleries/2015-02-24/top-10-most-beautiful-island-beaches-hawaii-australia
Among the renown beaches I had the opportunity to see (and all of them were a wonderful experience, but most were not so tropical - lol), I'll cite those which impressed me most:
Bondi Beach, Sydney
further (less tropical but what a sight!) - Ocean Beach, San Francisco
and a small beach in Crimea at the Black Sea (neither tropical)
https://en.wikipedia.org/wiki/Sevastopol
or, rather long ago, Watamu Marine National Park, Kenya
or on Helsinki's shore islands (not tropical at all, but beautiful)
And, regarding some of the great Mediterranian beaches, they were/are often perfectly organised - for comfort, sports, visiting, tours, gastronomy, arts, wellness, glamour and fun (but often, you hardly see the beach - lol):
Rimini Beach