Anyone have any suggestions for hotels in rome, Florence and Venice ? We will be spending 12 nites i

My husband and I along with another couple are planning a trip to Italy sometime at the end of March - april 2012. We have never been there and are desperately southwest airlines fares southwest airlines looking for suggestions for a 10-12 day itinerary. We are flying into Rome and would love to visit florence, Venice and Tuscany, if possible. We are in our 40's and love to see museums, pretty much all the historical places/landmarks, restaurants/bars, shopping.
Considering your likes, I think you will find that three or four days in Rome will barely southwest airlines fares southwest airlines scratch the surface of what you can see and enjoy. So don't worry about taking day trips outside of Rome. Three days in the city of Florence, with maybe one day to go to one location in Tuscany as a day trip will work just fine. The same os true of Venice. Two full days for the city, then one for an excursion to someplace like Ravenna, will be fine.
By the way, when booking southwest airlines fares southwest airlines on line, look for the multi-city option in the search box when you start entering info on your destinations. That is how you get an open-jaw southwest airlines fares southwest airlines ticket. Avoid backtracking. It is a waste of time and transportation money. It's usually better to start in Venice and fly home from Rome, because most flights from Venice to the US are early morning flights southwest airlines fares southwest airlines and it's a hard to get easy transportation to the airport early there.
Some things we did to save time was to book our tickets to museums in advance--just make sure you bring them with you and do not miss your scheduled times. This saves a lot time generally spent "in line".
We usually travel abroad every summer and always rent a car, but chose not to in Italy. You cannot use a car in Rome, Venice or Florence and the trains southwest airlines fares southwest airlines are great and easy to use. You could always rent a car in Florence to drive through Tuscany. We definitely wanted to see Siena, but did not have enough southwest airlines fares southwest airlines time. My husband wanted to drop Pisa, but we were traveling southwest airlines fares southwest airlines with our teenagers who wanted their picture with the leaning tower!!
Anyone have any suggestions for hotels in rome, Florence and Venice ? We will be spending 12 nites in Italy (March 28 - arpil 10). Flying into Venice and flying out of Rome. How many days/nights do you recommend for each city ?