Posted this over on Italy after I got back, but am finally moving it here and adding a couple things.
Early morning departures: I had planned on taking the first train to the FCO airport, which would have given me a couple hours before the flight. But the owner of the apartment I rented let me know that although the train may run that early, but buses to the train station would not, and it's be a half hour walk to the Trastevere station. He didn't think much of the area around the station that early in the morning, and I didn't think much of a half hour walk with a suitcase that was a lot heavier than when the trip started. He arranged a driver to pick me up at 5:15, which got to the airport in plenty of time. Hardly anyone is up that early. Cost was 45e, which is comparable to regular taxi.
Heavy stuff: Books are heavy. That paperback museum book seems lightweight until you buy several of them. Think twice about buying books if you're carrying on. (I'll forget this rule before the next trip).
Getting up early: Actually, not a lot of people (tourist people especially) are out before 9. If you can go to the Pantheon by 9, it's a much nicer and more peaceful place. It's beautiful anytime, of course, but mornings in Rome are lovely. This is true of Florence as well. I was out there about 8 or so, so not crazy early, and there were vendors starting to set up but not many people. It's a good time to look at the Baptistry doors in situ (they're reproductions but pretty good ones and nice to see in their intended location). If you're a photographer who wants no cars/people, maybe try 7 or 7:30?
Water: Rome has water fountains everywhere. Maybe technically just "fountains", but unless it says otherwise, it's probably potable. They even have a couple bottle filling stations that spit out natural or fizzy water (one by the colosseum and one outside the Vatican by Cipro metro station). So very civilized. (The airport didn't, but we've established that money is more important that recycle, reuse, etc. The tap water from the bathroom sink is still better than London drinking fountain water).
VA refund: Best part! It's easy. I was transferring through another European city, but thought I'd try to get the stamps here instead of hassling with it later. The people in front of me in line were doing the same, but were actually told to get the stamp in Italy. If you're carrying on, go through security, and immediately after before going to the gate and passport control, look right and find the line. It's even open at 6am. The line took 20-30 minutes to get through although it wasn't really all that long, so plan for that. Maybe some people didn't have their forms already filled out? It could be a pain if you get behind a tour group, but hopefully they'd be checking their stuff and would deal with this outside security. There are signs on the office that make it clear- No Items, No Stamp. But this guy wasn't checking items. Then they have the mailboxes right there for the different tax refund companies, and no stamp needed if mailing from the EU. Not sure the places were open if you want to get cash back, but I'd rather have the refund on the credit card. Now to wait and see if it actually happens! (Still waiting and will probably be waiting for some time).
Credit cards: Chip and pin still not reliable. I had a USAA credit card, which worked fine when there was a person to have me sign, but went to a couple gas stations after hours and it didn't work. Keep the tank half full, just in case.
Local bus tickets in Rome: Available at the tabacchi shops, but those shops aren't always right where you want them. Buy a couple/few and save for when you'll need them.