We don't have much for bears here in Alabama that I know if, but we were discussing this at work on day. A female coworker (who knows I carry and we've discussed it at length) asked me if I thought using a .45 would stop a bear.
I just told her I'll shoot until one of us is dead. They wouldn't find me laying dead with a half-empty magazine, that's for sure. I'd fire it dry and then shove it in an eye socket or something if I could.