I'm all for the "run away while/if you have the chance" side of the argument. I've always been told by the members of my family who have weapons permits (and trust me, they do carry a firearm pretty much everywhere), that if the opportunity presents itself, get away. Even if you are armed, that's your best bet. You never want to have to use what ever weapon you're carrying, knife, gun, garden clippers, etc. And, if god forbid you have to use a weapoin in self defense, never attempt to wound the attacker. Aim to kill. None of that "shoot 'em in the knee" bullshit. Aim for the torso or head. If a knife is your only option, then if you're forced to use it, as stated before, go for vital areas like veins, and tendons. Get away and call the police. Seems like common sense to me...
Or, you could just try your darnedest not to get into situations like that in the first place. If you're in an unfamiliar area, or one you know to be 'hostile', travel in groups.