I went there last year. My wife planned our trip which was 5 days in Rome, 4 in Florence, and 4 in Lake Como. Lake Como was my personal favorite. Anyway, great city. The one piece of advice I'd give, which is counter to someone above, is avoid guided tours. Everyone on them looked suicidal while my wife and I chose where we wanted to go and for how long we wanted to stay.
I'd recommend Rick Steves book on Rome. (He has books on every major city, just google his name and Rome.) anyway, if you want any specific non-touristy restaurants I can help you. PM me.