http://en.wikipedia.org/wiki/Afghan_Girl check the link for confirmation, that is an amazing lens I really love mine and the results I get with it.
Anyway, I shoot Medium format most of the time. I have folders, I have a Pentax 6X7, I even have a Kodak Douflex twin lens. For me it is less of a question of what format, and a question of what type of camera today? I tend to carry a folder of some sort if I want a pocket point and shoot for the day, on vacation, and when I am hiking or rock climbing. I use the 6X7 for landscape, and casual stuff where I might want to have sharp focus, or better DOF control, and the weight is not a problem, that said I have taken it hiking but by the end I wished I had a backpack for it.
If I am shooting action, stuff I need a zoom for, things where I need both auto focus and a motor drive, I shoot with the 35mm. If I want something that only one of my 35mm lenses will deliver I shoot 35mm. They are also nice for vacation because of their size and the availability of film on the road.
I do have to admit, that sometimes no mater how heavy or awkward it might be I have carried a medium format to places I would rather not have because I wanted something only the lens on that camera would do.
I shoot Stereo Photos only in 35mm because that't how I roll.