We also managed to get away to Rome over the January break. I think it topped both of our lists as our favorite city we've visited. Since it was the low season, we enjoyed both the sunshine (and significantly warmer temperatures than Scotland) and lack of crowds.
Tourist highlights? Colosseum (right down the street from where we stayed), Parthenon, Trevi Fountain, Vatican, Sistine Chapel, etc, etc... Check.
Delicious food (and drink)? Pizza, pasta, cheese, wine, grappa, etc, etc... Check.
Oh, and visiting the cat sanctuary so I could fall in love with adorable, three-legged hobo cats?
Probably my favorite part.