I'm not sure I could cover the broad spectrum of hunting and defense with just 3. Is the hunting local or world wide. Small, medium or dangerous game? For survival or for sport? Defense --- are we defending your home against "Bart the Burglar" or the Chinese Army in a Red Dawn scenario?
A 22 LR for small game
A 204, 223, 22-250, class for Varmint hunting
A 308, ect for medium game
A large caliber stopping rifle for dangerous game
A semi-auto in 223 or 308 for defense
Possible some of these could serve a dual purpose. If we were defending against a foreign army I would want what our army or the invading army uses.