Ten percent of Italy's wine grape crop is Sangiovese. A bottle of Chianti has to contain at least 80% Sangiovese. Brunello from Tuscany is made from a particular Sangiovese clone, is often highly rated, and can cost north of $100.
Sangiovese has great acid, making it ideal for foods with tomatoes. Spaghetti and meatballs, anyone? The wines are savory -- savory being the opposite of sweet -- so rather than pronounced red fruit flavors found in many New World wines they're more earthy, maybe mushrooms, peppers, or tobacco. You often get red cherries from California Sangi.
Sangiovese has never quite caught on big as a varietal in the U.S.