I wouldn't go to the Sistine Chapel. I went, got there an hour or so before opening time, still stood in line for two hours and then when I finally got to the Sistine Chapel itself it was so full of tourists, it was impossible to really take it all in. (And this was in November in the rain.) I'd go to St. Peter's instead. I'd go to the Broghese gallery. It's open until 7 pm. The Bernini's are fantastic and it's in an old villa.