I am interested in seeing the answers of this simple question. If you to go on a tour then which 3 canon lenses you will prefer to keep with you. I purposefully don't want to mention the place where you are visiting is famous for landscapes,architecture or wildlife.
I don't shoot Canon, but i'd take my 14-24, 24-70, 70-200 and 1.4 and 1.7 extension tubes. That should cover all but the most extreme wildlife, for which i'd have to rent long glass.
I have every lens I ever used for a challenge listed on my profile page, but I only really own 2 lenses right now, but I feel they give me a lot of flexibility in a small package...