Just got back from Italy, and spent a couple of nights at the Excelsior in Florence. Terrific hotel, great location. No need to stay overnight in Pisa, easily reachable from Florence. Stay in Florence an extra night. (I also echo skipping Naples, and adding that day somewhere else -- I myself would add it to Florence, and either spend it there, or easy trip to Siena or Lucca).
This thread will show you the exact room we stayed at in Florence at the Excelsior.
http://www.flyertalk.com/forum/starw...er-thread.html
And we stayed at the E&R in Venice a couple years ago.
Our Grand Canal view room at the E&R and our Arno River room with balcony at the Excelsior in Florence are two of the best hotel experiences we have ever had. Highly recommend both of them.