We've got a Yashica Mat that came with a case. Its in good shape and I used it until I had to change the first roll and realized how much it got in the way. I left the case off and its stored in my closet to keep it in good condition to up the resale value . I just got a Luna Pro F with an immaculate leather case. It makes the already bulky meter even bulkier and it now resides in the same box as the Yashica case, awaiting resale. My wife's DSLR came with one of those neoprene Zing cases, it was a little too phallic for her (and my!) tastes. I'd rather just wrap the camera in a spare stocking cap or small rag. When out-and-about I prefer to let the camera hang from my shoulder or neck. I carry extra lenses, cameras, film, meter, etc in a canvas shoulder bag. I use the bag every day to carry things to work but I'm thinking about getting an insert for it to make it a little more convenient when I'm using it for photographic purposes.
I've got a Minolta enlarging lens that came with a case like narsuitus shows. I DO like that for keeping the lens clean and safe when its not in use but I wouldn't want to carry something like that around.