As said before, research and then get what you want. Personally I have a couple Irish Wolfhounds. They are great for a shock value, and if their "people" are threatened they will defend them, with their lives. They do eat a lot. (8-10 cups of food a day per dog) Their bark is pretty loud (2am jumping outta bed to fend off zombies with ringing ears, and not remembering how you ended up outside in your underwear LOUD ) they are sight hounds, which is a plus and a minus. They are big enough to take down a deer, and strong enough to drag it back to camp. They were originally bred to hunt down and kill wolves. (There are no native wolves in Ireland anymore. yes humans helped) When they go after something, it takes something short of an act of God to call them off. They are gentle giants though, the first male we had let a baby play with his ears pulling and yanking out hair, without complaint (a friend of the family wanted the pic) the average live span is about 7 years, and the breed is plagued with problems (cancer, heart problems, bloat all have happened to my past IW's)

Wolfies would be a great resource, but i look to a historical example. smaller, self reliant dogs were the dominate dog during the time when dogs were part of survival. Native Americans, Settlers, and colonists all had medium to small, tough, self reliant breeds. if i was looking for a dog for a survival situation that would be a part of my factors.