I went to Spain last summer (which I think is similar to Italy in that it's relatively laid back fashion-wise), and wore a lot of sundresses (mostly from Anthropologie), and some flat woven sandals from J Crew. I was there for sightseeing (ie lots of walking), and I only had carry-on luggage for a little over a week (I don't trust checked baggage, hehe), so I only packed flats since they would be ok for all situations and take up less space in my luggage. Ideally, I would have also had a pair of lower wedge heels for days I didn't walk as much.