357 or 44 mag.?
Go with the 44 Magnum! Check out the Ruger Redhawk for a double action revolver, the Ruger Blackhawk for single action, and the TC for single-shot. All are excellent firearms, and will give you years of good service.
Leave the 357mags. at home - good for pers. defense, but on the
small side for big game hunting, and definitely underpowered for
bear.
Another option however, you might want to look into the 45Colt.
Most factory loadings are mild, but there are some that will keep right up with the 44mag., and a few that will surpass it in power.
Can really be awesome if you handload it.
Again, the Ruger Redhawk, Blackhawk or a TC will do.