Growing up in Alaska, I've spent plenty of time in the wilderness with nothing but a fishing pole, a bottle of bug spray, and a back pack full of fresh salmon. When I bought my first pistol, a Ruger P90, I carried it whenever I got too far from civilization (read... more than 100 yards from the road). I never thought it was enough gun to stop a charging bear, but it would certainly make some noise. Then, when I inherited my dad's 6-inch Dan Wesson 357, I carried that. These days, I carry my S&W 460v in a chest holster.
Over the years, I've seen bears in the wild many, many, times (as close as 10 feet once - had to fire a few shots from a 12ga to shoo it away from the airplane while we were fishing). But, although I've never had to shoot a bear in a DLP (defense of life or property) situation yet, I certainly feel more secure these days knowing I'm carrying a hand cannon rather than the P90.
If I had to give up the 460, I'd certainly go back to the 357, at least until I could pick up a mid-length double action 44. But, the heavy X-frame S&W is just as easy to shoot as the 357, and 325 grains of hot lead at 1600fps might even make mama bear reconsider her decision to eliminate the strange looking two-legged threat to baby bear. So, at least for now, I'm going to hang on to it.
The truth is, if you're "bear smart", you probably won't ever need to pull the trigger. But, if you do actually have to shoot in a DLP situation, it probably won't matter what you're carrying. Because even though they do tend to make the carrier feel safer, most handguns are woefully under powered for that particular task.
(Keep in mind we're not talking about hunting, here. There are plenty of handgun cartridges that will take down a calm bear with a well placed shot. But, a sow protecting her cubs has a whole bucket of adrenalin pumping through her veins, and that's a totally different scenario.)