I've always been underwhelmed when visiting Venice, whilst there are so great locations and sites, its a real tourist trap besieged daily by a massive crowd of tourists, making it hard to enjoy some of the attractions and often the incoming tides flood the square etc.
i agree with Peter park away but try to take the canal bus in on the grand canal. It is smelly and a total tourist trap but beautiful. We went once & I wouldn't go back jus tbecause of the rip off tourism. The same withSpoleto a gorgeous mountain town & peaceful vs Florence.
As I get older I hate crowded places but I am glad I was in Florene & Venice once.