For my next trip in Rome I already chose my place to stay. First of al, the location is so perfect - you can go to all sights by foot, I didn't use transport to do that in my trip, and I think that Rome is this kind of city what you should explore travelling by foot. The street is very beautiful, the square is amazing in day time and at night. There are a lots of wonderfull cafes very near, but i recomend you take Viktor's advice in this question. My room was very big (bigger than flat which I booked in Paris) and there was everything I need.
Viktor is such a nice person, I had no problem with communication with him, his advice were very heplful, he knew a lots of interesting things about Rome and places to go. Thank you very much, Viktor, my room was cozy home for me, when I was in Rome :)