A Weatherby Vanguard in .308 Win will do everything he ever needs done in the lower 48 except grizzly bears, from now until he retires.

You have asked an interesting question, and I am serious about this. After much thought, if I could go back 40 years and talk to the young me, this is what I would tell him - Scout for the best rifle you can find, used or new. 270, 308, 7mm mag, 7mm-08, 30-06, 7x57 Mauser, 300 win, whatever reasonable deer caliber. Buy the best German/Austrian scope available, used or new. Hunt for the next 60 years and be happy. When you can afford a backup, buy similar to your first. Scope and rifle requirements remain, caliber can change if desired.

I am in no way saying that other calibers won't work. That would be in direct conflict to my caliber addiction, and therefore not rational.

What I am saying as an absolute truth, is that one rifle, in an effective caliber, with an outstanding scope, is everything that a man NEEDS.

What a man wants, as a desire, is an entirely different matter. I have killed critters with dozens of rifles, in at least a dozen calibers (maybe 2-4x that, just cant remember well at the moment), but just kept searching for a better mousetrap.