I have a large number of bags, cases, and pouches that I use to carry photographic equipment. Some are hard; some are soft. Some are large; some are small. Some are water proof; some are not. Some are padded; some are not. Some are used only for transportation, some are used only for storage, and some are used for both. Some are used for cameras and lenses, some for lighting, some for camera and/or lighting support (i.e. tripods, light stands, background support, etc), some for film and/or digital media, some for photo accessories such as filters and batteries, and some for equipment maintenance & repair tools. The material in the bags/cases/pouches varies from leather to cloth to plastic to metal to cardboard to a combination of the various materials.
Which ones I use depends on what equipment I am transporting, how much equipment I am transporting, and what mode of transportation I am using (i.e. plane vs. car vs. bike vs. walking).
When I travel with a light photographic load, I carry a small camera in a small bag or pouch that I attach to my belt.
When I travel by bike or on foot, I use a soft backpack and/or a belly pack.
My largest photo case is a hard 22x19x9 inch waterproof and crushproof case.