Well, like you say, a can of worms, and I'm sure there will be many opinions
I'll start with my current front runner is a 6mm-284, 28, or 30" 1:8 barrel, custom action, & AICS stock, aiming to shoot 105g Amax, or similar.
And see what abuse that gets me
My friend says the way I shoot, I'd be better off with a 20mm Anzio, whatever that is