We visited Florence in early October 2013 and absolutely loved this city. Even though we arrived at the Uffizi at 8.30am (opening time), the queue was enormous so suggest you purchase a Florence card (Firenze card) which means you jump the queues and gives you access to most attractions. You cannot visit Florence without visiting the Uffizi. It is amazing and you will need time to have a good look around (if time is limited at least allow 4 hours here). No photos allowed but we purchased a really good book on the gallery. The building was built in 1560-80 to house offices for Cosimo I. There is an almost continual wall of glass on the upper level which affords views of the Ponte Vecchio. The sculptures housed here have been moved to the Bargello and the ancient objects moved to the acheological museum, so the gallery now houses the most amazing collection of paintings in Italy.