Lens for travel in Italy

[cinvala]

I'm off to Italy for a month long holiday next September. It's not a photographic holiday per se, but I do want to take pictures. Having said that I want to travel as light as possible, a light tripod, cable release and one lens. I want a lens for my 7D that is good in low light, doesn't stick out a mile, ( i.e. is unobtrusive), I want to shoot street scenes, interesting people, food, country sides. Suggestions appreciated.