I have a backpack and camera case that I use but one of my first and favorite bags that I use for my gear is a surplus Swedish gas mask bag. It lacks the padding and compartments of actual camera cases but it holds all of my gear, has a outside pocket I use for filters/film and the leather bottom keeps the case pretty rigid. For a little extra protection I usually pack it with a thick piece of fabric or two but it's not something that I would want to drop. However, I appreciate that it doesn't scream "this is a camera, steal me!" while I'm out exploring.