Hiya Mate
Ive been to Rome a couple of times, and think its a great city!
Theres loads of places that are great to see, try to do as much as you can on foot, because its all the little side streets that hold the best surprises.
Places that are great to see include:
The forum- right next to the colloseum, the forum is where all the best roman ruins are, and where cesar is burried, probably my favourite bit of rome.
Palatine hill, this is above the forum, really nice gardens, and great views of rome, nice for an afternnon chill out. P.S. Its well worth buying a joint ticket for palatine hill and the colloseum, as it wont cost much/if any more than your ticket for the colloseum, plus it will save you a good hour 1/2 cue to get into the colloseum, as with this ticket, you bypass the main cue.
Trevi Fountain-Really nice down there, and a must see, but be carefull a few dodgy characters around (dudes givin the missus free flowers then asking for a 20 euro donation etc lol)
Chill out markets on the river tiber-Last time we went (in August) there was market stalls along the tiber (nr the vatican) including a few outdoor bars playing cafe del mar type tunes, was really nice there at night
The Pantheon-preferred this to the vatican tbh, better architecture, loved sitting in the square around it
Piaza del popolo-really nice place to chill out, nice square/bars etc, its a couple of mins from villa borghese and about 10 mins from the trevi fountain.
Villa borghese-Really nice park with some roman ruins, good place to chill
A tip for the vatican- If your after the cistern chapel, dont go on a sunday-its closed! lol, make sure your shoulders and knees are covered cos they wont let you in and you'll be forced to buy scarfs outside to be covered up, and dont expect the people there to be friendly, they was amongst the most arrogant people i have ever come across. But dont let that put you off if you want to go mate, its worth checking out, but there are much nicer places in rome to go.
If your looking for somewhere to stay id suggest somewhere near to via national, or termini station, as these are central points and its easy to get around rome from these destinations. We stayed just off via national, and it was about a 10-15 min walk to the colleseum.
Try to do as much of the sightseeing on foot if you can, cos theres some great sights off the beaten track, ruins here and there, and i think you'd miss out if you did everything on buses etc.
Some great grafitti as your coming into the city centre, took us by surprise.
Its also worth buying a return ticket for the terravision bus return to from the airport, as it is a good reliable service, and i think its only about 15 euro's.
Theres so much to see in rome, and unless your going for a couple of weeks, it is hard to cram it all in. I'd deffo reccomend the forum, the pantheon and villa borghese, as well as palatine hill.
When are you planning on going mate? hope you have a great time
Sorry for waffling abit lol, but theres so much to do in rome
Im sure you wont regret going, we loved Paris before we went to rome, cant even talk about it in the same breath now, theres no comparrison lol