Kent Staubus , Feb 26, 2012; 09:56 p.m.
Because of internationally famous pickpockets, I would take the bare minimum. I would not run around Rome with a bag full of stuff. I'm thinking tokina 11-16mm f2.8 and 17-55mm f2.8. I would also take a second camera of some kind. No way I'd do an important trip without a back up.
One of the things I've been coming to think is that the lenses I'll use on a trip are exactly the same ones I use at home. Exception might be if you go on a wildlife tour and don't photo that at home much, etc. I have three zoom lenses I use at home, and have used exactly the same lenses in Hawaii, Iceland, Canadian Arctic, Florida, and this summer will be in the European Arctic. I don't change my style depending on where I am. I am buying a small D5100 for back up camera. Small, flexible, capable. And, cheap if it gets stolen or destroyed.
Kent in SD