The fellow who gave us out "Bear Aware" course noted that if all we could carry was a knife, that it should have a minimum of 10" of blade. I showed him my tanto and he said "That would do it", however a wakizashi or Katana would be better. A 12 bore pump with heavy slugs tops it all.

I always have my Leatherman - with 2 - count them - 2 very dangerous short blades (knife and saw). This belt tool gets used, most every day for something or other. Before getting one (birthday present) I didn't think it necessary as I always had a folder in my pocket. After getting that first Leatherman Wave, I could not believe how important a tool it was - every day use - always on my belt.
Currently packing a Leatherman Sidekick.