Debaser and Lebell... you forget ninjas.
In regards to the original thread, I can't speak to carrying a handgun concealed, as I never have. For hand to hand weapons, though:
1) Anything nearby (stick, trash can, child, etc)
2) Small, double sided, straight sheath knife. It comes out quick and it's easy to use. Something like the one on the left here:
3) A smaller stiletto, or a boot knife... like the one on the right in that image. Only reason I prefer the thumb knife mentioned before is that it's easier to conceal.
4) My keys, or a pen that I always carry. They'll do in a pinch.
And of course,
5) My ninja skills. But that pretty much goes without saying.