In support of some of the others don't rule out landing in FCO. Italy has an excellent high-speed train network and it's about 2 hours from Roma to Firenze. Also consider Milano. MXP is a fair way out of town, but LIN is very close (once I actually walked from LIN to Milano Centrale but I wouldn't recommend this approach - the buses run regularly and are cheap). There is also BGY but this is a fair way out of town and less likely to come into play.