When I am planing on shooting something I need to die, I choose larger calibers. I started hunting with a .243, then .30-06 and now .338-06. The heavier bullets hit harder and down game faster. I have a .450 Bushmaster, .444 Marlin and .414 Supermag as well.
I shoot mostly 9mm in USPSA, Steel Challenge and 3Gun, after years of shooting .40. It is cheaper, easier to shoot fast and more reliable. I have several rimfires I shoot as well.
For defense, it varies.
While I guees I used to ascribe to a medium philosophy, I am more about small and large now.