When traveling, I generally carry one manual SLR, often times a Zenit, Praktica or a manual Minolta, i.e., MC SRT II with a Minolta F1.2 58MM lens. But along with that I try to also carry a small P&S for quick shots, or if I want someone to take a shot of me and they know nothing about cameras - the world is full of them!!! I also sometimes carry a Minolta X700 with the 1.2 Minolta lens. I like manual cameras, but they are generally heavy because of their metal construction, most of the time.
On top of that, I must admit I also carry my faithful Fuji S700 digital cause I generally travel with a team and it's easier to download a bunch of digitals rather than scan a 100 or so pictures. Thus far, my Olympus Stylus and XA have filled the bill for lightweight and "concealable" 35MM cameras, as well as a little larger Canon ML or at times even a Canonet 28.