I agree on the side of 30 cal big game hunting. I don't even like shooting gophers with .22LR because often it takes two or three to really put them out of their misery. It's not enough in my opinion to just mortally wound, you need bang flops, and that's why I usually opt for my .223 when gopher eradication is my mission. They are no doubters (read gophers look like they stepped on a landmine!)... but then again we're talking deer here.
I think Alberta has the right idea about .243 or bigger.
Let's all be humane, right?