I am passing along these tips on Italy shared with me by a veteran overseas traveler. -- Deborah Whitaker
WHAT TO SEE: The biggies are obviously the Colosseum, and the Roman Forum, the Pantheon, the Vatican museum, St. Peter's Basilica, the Spanish Steps, Trevi fountain, Piazza Navona and Campo de Fiori.
The Vatican museum and Basilica can take a full day by themselves, and even then you have to to get up early. The Colosseum and Palatine Hill (Palatino) and Roman Forum (one ticket gets you into all) can take another full day.
The Palatine Hill actually may be more interesting than the Colosseum. If you’re interested in seeing both the Colosseum and Palatine, I'd suggest paying the 8 euros per person extra and buying into a guided group (found in front of the Colosseum) for a 45-minute talk at the Colosseum and an hour’s guided tour of the Palatine HIll -- supposedly founded in 752 BC by Romulus to become the Beverly Hills of the Roman Empire.
A TIP: if you walk 5 minutes past the colosseum to the entrance of the Palatino, you can buy the same ticket with virtually no line.
With a map, you can walk downtown Rome -- the Spanish Steps, Trevi Fountain, Via del Corso (the famous Rome shopping street), the remaining wall of Hadrian's Temple, the Pantheon, Piazza Navona, Campo de Fiori. You could also add in there the Vittorio Emanuale monument, referred to by the Italians as the "wedding cake." This is an ostentatious monument built by Mussolini to King Vittorio Emanuale, who supposedly united Italy in 1861 ("supposedly" because some would argue Italy still hasn't really been united).
MUSEUMS: Explore the Villa Borghese simply because of the statues. Reservation needed and they kick you out after 2 hours. Villa Borghese is one of the big parks in town, just north of the U.S. Embassy, and is nice to stroll through during the day. Great overlook of the city from the park’s west side. The other things include Ostia Antica and Tivoli, about 90 minutes by train outside of Rome. Ostia Antica is the ancient Roman port, now a city of ruins. Some buildings remain intact, and you can walk through the area almost without restriction. Tivoli is a pretty little mountain town, and alternatively if you'd like to see an Italian village, you could take the train to Orvieto, on a little hilltop about an hour outside of Rome, for a long day or maybe an overnight. It's just inside Umbria, to the north, and there are vineyards around the area.