What Weapons to use while Traveling through a Deserted World

Heavily debated amongst fans of the post-apocalyptic genre, this topic. I would almost suggest a white flag - after all, people with guns will be part of the problem.
Pretty soon after any truly serious disaster, the population will rapidly be reduced. Staying put and in a place with lots of canned food will in in most cases be fully sufficient. However, the following weapons may be helpful, e,g to hunt or or fend off wild animals (yes, also the human kind):
- A Knife (indispensable)
- A Crossbow (re-usable ammo, easy to maintain and use)
- A Bow and Arrows (re-usable ammo, but needs considerable power and training)
- A Gun (high maintenance, risk of shooting off your own foot)