Finnegans Irish Pub, Rome
Finnegans is an Irish owned bar in Rome. It feels like a typical Irish bar, with good Irish brew (Guinness is a given - although I am not a fan of the drink myself). It is a great bar to go to as it is not on the main streets of Rome (but is still in the historical centre) and therefore a lot of the people who come here are locals - well okay, a lot of them are Irish or from the UK, but they're not likely to be the same tourists who were checking out the Trevi Fountain or Spanish Steps.
The atmosphere is great - sit at the bar and have a chat with the staff, play a game of pool (billiards) in the back room, sit outside, or sit at one of the booths/tables and just relax. When I went here it was because there was a 'friendly' football match on - Ireland v. Italy - Italy won 1-2. If you're looking to watch anything sports related to Ireland (Rugby, football, gaelic football, hurling) - they will, more than likely, be showing it here.
So, if you're in Rome, but for some reason feel the need for a good Irish pub - then this is your place.
Sometimes after a very long day of walking, and touring, and walking some more, wine just won't cut it. Rome can be dusty and hot and beer is a necessity for such conditions. My tour guide said this was her regular spot and she and her friends even met us out for a couple of pints. It's a typical pub with football on the tv (or the Simpsons) and a broken toilet in the back. But you can sit outside and enjoy a Guinness and a smoke on the little back street patio. It's wasn't very crowded and was mostly occupied by students and other Irish/UK locals. It claims to be the ONLY Irish owned pub in Rome/Florence, but if you're looking for more of a "scene" I'm sure there are dozens of other pubs spread throughout Rome that would provide the same beverages and similar atmosphere.
Dress Code: Definitely casual dress. I'm sure you will likely spill something on yourself here.