Being from the UK and us having very different opinions on firearms to the guys in the US not to mention very different laws, the only weapon I tend to carry is a rather heavy manfrotto tripod and a 7D.
If I had to, I'd swing the tripod head first at any would be attacker or thief. Failing that, if my life or well being was in danger, my weapon would be a gift of the camera and tripod. Then I'd leave quickly.
Ain't no point in losing my life or brain function over a camera.