.44 Magnum is my advice. Or better, .44 magnum is a certainty, a safety. Now, which gun? Depends on the kind of gun you want: if you want a double action revolver, my suggestion is Ruger Red or Super Red Hawk (maybe Super Red is better for hunting); if you want a single action, Ruger Super Blackhawk or Old (not New) Model Vaquero (if you succeed in finiding one), the first more suitable for hunting, the second for fun.
I've an Old Model that is, in my opinion, the best .44 Magnum I've shot, really very strong, accurate, powerful and funny!