If you are planning to stay just a couple of nights I recommend the Grand Hotel Baglioni. It is directly across a plaza from the train station and reachable via an underground walkway from the station. You are within easy walking distance from all of the major sites in Florence, lots of good restaurants nearby, and an internet cafe a block away so you don't have to pay the high price to connect in your room. The rooms are European small but very clean. Very friendly staff and concierge A big plus is the A/C is very efficient, we went in August and were very comfortable. It has a restaurant on the top floor that overlooks Florence and is where breakfast is served with a view.