In February we went to Pizzeria Dante in the Oltrarno [Piazza Nazario Sauro 12r]. It was hip and fun, but not too trendy. Atmosphere was typical Florentine. Food was fantastic. I had penne arrabiata. Price are a little higher than your average joint, but it's worth it. But I do love those restaurants (all over Rome especially) where you can get a half litre of wine for 5 euros!