Florence is easily accessible and you can walk from monument to monument in little time, so no matter where you stay you will never be far from the sights. If you are arriving by train, there are many hotels near the station, or a popular area is the Santa Croce district.
In Venice the Hotel Belle Epoque is nice and reasonably priced. It is really close to the train station, and right next to the water bus services.
http://www.belleepoquehotelvenice.com/ about 6 years ago