Every year a list of the best Italian beaches is published- the best according to various criteria, primarily environmental. This year there are 227 listings, and the best regions are Tuscany, Marche and Liguria. Surprisingly, expensive Sardinia, known for its beach vacations, is low on the list.
The entire list, organized by region in alpha order, can be found
here.
(Left, my beloved Castagneto Carducci, south of Livorno on the coast of Tuscany, which has made the list for many years)