For NA BG, I subscribe to the late Allen Day's school of thought. Two identically set up .30/06's (although Allen preferred the .300 win mag). Cause stuff breaks and a .30/06 is all you need for NA big game.
If you really want two different calibres then I am with bsa, a .270win and a .338win and you are set.
Mr. Day communicated the same pairing (270 & 338) to me as well. I've made good use of a 338, just need to get around to picking up a 270.
