In Florence: Definately the Westin Excelsior - 6 stars in my opinion. See my trip report on this hotel and Excelsior Rome - not sure I'd recommend.

We stayed at the hotel Minerva, We booked it through city breaks brochure and got 3 nights for the price of 2.

It was a wonderful hotel near to everything. We had a balcony and at night a string quartet would play in the square outside.

It also had a pool on top of the hotel staff were friendly. Tea and coffee in room and they put goodnight mats on the floor for you which is a nice touch.

I would stay here again if I went back.