My basic all-around kit is one rangefinder body with a 35mm and 50mm lens. That will cover 95% of my lens needs.
If I am traveling, I will take my other two rangefinder lenses with me (21mm and 90mm). If I am just going about my business and am not specifically heading out to make photographs, I will carry my RF body with a 35mm lens attached for unexpected opportunities that may pop up.
The Leica M passion: From the inside it's hard to explain; from the outside it's hard to understand.