the best of Rome in 4 nights and an extra afternoon and evening

Sounds like you have 4 days to see Rome, you can see a lot in 4 days. Rome has literally hundreds of things to see and do. There are hundreds--no thousands--of websites that will give you a list of things to see and do (Google Rome). Here's something by Rick to get you started: planning your time in RomeAnd click this link and then scroll down to the Rome section: Rome!

Thanks Kent. That's the trouble- so much to see and do. Maybe I should have asked-'name your top 5 things to do in Rome.

Here's Rick's answer if you had 3 full days (note you'd have to have his book to know what the Caesar Shuffle is, although he may explain it in the links I gave you above):"On the first day, do the "Caesar Shuffle" from the Colosseum to the Forum, then over Capitol Hill to the Pantheon. After a siesta, join the locals strolling from Piazza del Popolo to the Spanish Steps. On the second day, see Vatican City (St. Peter's, climb the dome, tour the Vatican Museum). Have dinner on the atmospheric Campo de' Fiori, then walk to the Trevi Fountain and Spanish Steps. With a third day, add the Borghese Gallery (reservations required) and the National Museum of Rome."

But since you asked, my top 12 (every traveler will have a different list) are:ColosseumRoman ForumSt Peter's BasilicaVatican MuseumPalatine HillPantheonBorghese GalleryNational Museum of RomeCapitol/Capitoline HillCapitol Hill Museumokay, Trevi Fountain and Spanish Steps as walk-bys

Thanks for the comprehensive reply. I am more confident that we can cover a lot of ground whilst having a fantastic time and lots of coffee and cappuchino. We are seeing Pompeii from Sorrento - does Ostia Antica offer somehing extra?

There are so many incredibly beautiful churches in Rome. We have been to Rome five times and have not made it to Ostia yet. The Pantheon is a must see on every trip. We finally made it to Minerve, San Giovanni in Laterno, and Scala Santa on the last trip--all very worth seeing. The Spanish Steps and Trevi are walkbys but do toss some coins in the fountain. The Baths of Caracalla, Aventine Hill, and Protestant Cemetery are also worth a visit. You will love Rome--have a great visit!

Did this last winter: Not in order!

Colosseum
Forum
Vatican museum/St Peters (Angel Tours)
Spanish Steps - window shopping
Cappuccin Cript
Pantheon
Piazza Fiori
Jewish Ghetto/theatre district
Ostia Antica (take Metro for a great day trip)
Oveito (day trip by train)

We allowed lots of time for just walking around and exploring off the beaten track- away from tourists on sides streets

Christine: You asked about Ostia, you're going to see Pompeii and some would say Ostia is similar to Pompeii, but it's a lot closer to Rome than Pompeii, and (I like the way Rick puts it) "Ostia gives you a more complete and gritty look at Roman life" than Pompeii. Ostia is 45 mins combination metro/train ride from Rome. But you can only do so much, priorities vs. time and energy available, etc. Some travelers, with limited time, don't do both Pompeii and Ostia.

I don't have much advice for what to see-we only stayed 2 days and saw the Colosseum,Palatine Hill,Trevi fountain,but what would suggest is using the Metro instead of Taxis.It is MUCH cheaper than taxis(and faster) and easier than the buses.

I agree with all of the above--my most favorite thing though is the Borghese Gallery and eating gelato at every opportunity.

I'd also suggest having lunch or dinner in the Trastevere section of the city. You can take the bus there.