Well after reading through all this I'll throw out something.

To me, anything considered "dangerous" deserves the best you can handle. Let me say that last part again...THAT YOU CAN HANDLE. I just recently acquired a 500 S&W. It's a lot of fun. I would not, at the moment anyway, take it out for hunting or defense of anything. In my opinion I'm not yet proficient enough with it. Right now I'd carry my .44 Redhawk with 340gr hardcast bullets. I can hit what I aim at with this and could probably get off at least a couple aimed shots if given half a chance. (I'd MUCH rather have my .340 Wby doing the shooting if I could help it)

Is a .357 "enough" for bear? Well, it's a hell of a lot better than fingernails. Would I prefer bigger? Conditionally, yeah. All else being equal (I'm talking shooting proficiency here) you can't go "too" big with an angry bear IMO. Even with rifles ask most any DG guide what caliber you should bring and they'll say something to the effect of "What you can shoot?"

You want something bigger for bear defense? Sounds like a good reason to buy another gun to me. Having said that if you buy a bigger gun but you shoot the .357 better...take the .357 anyway.

JMHO

If there's one thing I've become certain of it's that there's too much certainty in the world.