There are so many adorable, small Tuscan hill towns worth exploring -- San Gimignano, Montepulciano, Volterra, Monteriggioni, and my personal favorite, Pienza.
Pienza is the perfect Renaissance town planned and built by Pope Pius II. It was originally a medieval town called Corsignano, but when Pius II became Pope in 1458 he decided to use his humanist education and immense resources to build an ideal city and a retreat from Rome.
Today Pienza retains its renaissance beauty and, although small, is a wonderful day trip from Florence. It so beautiful in fact that it was declared a UNESCO world heritage site. The city also sits on the edge of another UNESCO site, the stunning Val d'Orcia. This is the famous Tuscan valley used in many movies.