I wouldn’t skip the Vatican’s Saint Peter’s Basilica. Also the Colosseo (which is cool to see just on the outside as well) and the Foro Romano next to it. You can do the Spanish steps, Trevi fountain and Pantheon all in one easy walk (and all for free too).

I’d say those are the minimum “must-see” things, and the rest depends on what you like (castles/churches/squares/paintings/villas/gardens…)

Yes to all the above. One of my favorite things in Rome has been to hang out in the Piazza Navona. Lots of street artists sell their paintings there. Lots of outdoor cafes.

My favorite part of Italy was the smaller less crowded areas. So see the Colosseum for a couple hours then experience the FOOD. Get some coffee and a stuffed croissant at a cafe and just feel the city. Those were my best memories there. If you’re looking for more popular attractions go to the Pantheon and the Piazza Navona. Also make sure to check out the farmers market- less touristy souvenir items, lots of fruit and interesting jewelry and clothes!

You can visit all the city centre in just one day, if you walk quite fast! I would recommend to see San Pietro and Musei Vaticani, you can’t miss (at least from the outside) Castel Sant’Angelo and the Colosseum, Piazza Navona is my favourite, then Piazza di Spagna.

Fontana di Trevi and Fori romani, of course… All the “famous stuff” you can’t miss.

But, if you have the chance, go to Frascati and try AMAZING food and wine, famous in all Italy :)

There are lots of attractions in Rome to visit and enjoy. Most famous are :

1. Beautiful Vatican city

2. Colosseum

3. Roman Forums

4. St. Peter’s Basilica

5. Pantheon

6. Trevi Fountain

7. Spanish Steps

You have only three days so you can’t cover them all. But if you hire a car there then you can cover more places. These are some good car rental companies which provide low priced rental deals there with great services. You can try anyone of them.
http://www.fiumicinoairportcarrental.com
http://www.carsrentalitaly.com/rome-city-car-rental.html