We booked a tour with a company, Enjoy Rome, to see the Vatican Museum, Sistine Chapel, and St Peter's (3 hrs). They are Rick Steve recommended. The negative is that you have to visit their location the day before and pre-pay for the entrance tickets and tour, then meet them the following day near the Vatican. I am not sure if we are then standing in lines for them to purchase tickets once we get to the Vatican, since we have pre-paid. Has anyone used this tour group?
Then today, I received a fax from the Vatican Museum, that they can accomodate us and that it is an English speaking 2 hr tour of the Vatican Museum and Sistene Chapel (appears not to include St Peter's). No queing in lines, you enter thru a side entrance to their guided tour desk...then I guess we could visit St Peter's on our own. What option would you choose?