So, seems like visit the Shul/musuem (first see if you can get a tour and not just walk through it by yourself - ps there's a student discount of like 1 eur pp). Go to Academie to see David. Walk around town, see Ponte Vecchio bridge and head to Pisa to see the tower.
Would be nice to find out about Ruth's Kitchen (I emailed Florence Chabad), otherwise looks like we'll be bringing food from Rome.