Italy is our default holiday destination. Been to lots of places but always seem to end up going to Italy when we can't decide where else to go. Love the place. The people don't give a wet slap about anything, the weather's pretty good. It can be expensive in Rome, but then you're visiting a capital city, it's expensive in London too.
I would agree with Tony, if you can get to Florence then please do, one of the most beautiful places I've ever visited.
Avoid restaurants/coffee shops that are on popular squares, you will pay through the nose. We once paid £14 for two ice creams, didn't realise until we were walking away because everything cost a trillion lira in those days and it wasn't until I had supped a few mouthfuls that I did the maths in my head. "Enjoy that ice cream," I told swmbo, "you won't be getting another from that shop". Ahhh but we were young then...