Excellent advise and tips from everyone! Thank you. I know it is corny and touristy but has anyone used the "hop on & hop off" bus to get around to the various sites?
As far as interests...I'd prefer not to spend time in a museum (and yes, the entire city is a museum!) but I do love architecture, ruins, fountains, cathedrals, and also love stuffing my face and sitting at a cafe people watching. One of the days is my birthday and I haven't decided whether to find a splurge restaurant or just eat pizza & gelato all day. I know I can't go wrong with either choice.
Tlvyyz, thanks for the heads up on the airport. I am really glad I switched my departure flight from 9am to 11am. It sounds like I will need the extra time.