Any handgun is a poor choice for bear defense. Big rifle or a shotgun with hardcast slugs is a better choice.
If you really want to carry a handgun for bear defense, .44 mag with hardcast (think Buffalobore
http://www.buffalobore.com/ammunition/default.htm) bullets is the minimum. These should allow sufficient penetration to do the job. After that, you step up (.454, .460, 500S&W). You want a bullet that penetrates.
As for deer hunting, .41mag or .44mag is my choice.
Defense against two legged critters, .357mag, .44special or .45acp.
So, in essence. a .44 mag revolver could be what you want. Heavy, hardcast bullets for bear, 240 gr. bullets for deer and .44 special for home defense. S&W makes nice revolvers, as does Colt. I happen to prefer Ruger, but as always, YMMV and IMHO.