Agreed on the Florence markets. The best is the 2-in-1 San Lorenzo Market, an outside rabbit warren of stalls selling everything but focusing on clothing & leather goods. Right next to that is a two-story structure called the Mercato Centrale, the food hub. Highlights here are the best prosciutto house in Florence and Nerbone, a 150-year old stand that sells boiled beef sandwiches on a crusty roll, with a dollop of pesto sauce. Might not sound good, but believe me, it is. College students live on them, at a cost of about 3 Euro.
One more thing. We did an 11-day trip several years ago that originally was going to be--besides 4 days in Sicily--5 days in Rome, 2 in Florence. A buddy of mine had just returned from 4 months in Florence teaching art, and he advised me to switch it around, which we did with 5 in Florence, 2 in Rome. Great advice. Yeah, in Rome we did the Vatican & stayed near Campo Di Fiori, walked across the Tiber River to Trastevere for pizza (Dar Poeta!), and it was cool. But Florence creeps up on you. If you can, stay in the central area, near the Arno River. It's magical--besides the Uffizi gallery, there are tons of churches where you can walk right in, for free, and see frescoes from the Medici days. Incredible.