Semi Auto .308 carbine (M1A Socom or Remington 742<or modern equivilent>
keep a dot sight or 4x scope on it for Self Defense
they will protect from even armored two legged varmints and do well against medium and large game.
Pros:
simple/reliable action
accurate
good stopping power
good range
ammunition widely available
cons:
Overpenetration for indoor use
usually on the heavier side
relatiely low maximum ammunition capacity. (up to 20 rds in reliable magazines)
if big gameisnt a concern, then go for a AR design in either 5.56mm or 6.8mm
the 6.8 is more powerful and can be used to hunt dear but the ammo isnt very common and can be hard to find as of yetand it isnt the cheapest. Magazine hold up to 28 rds.
the 5.56 is everywhere and really cheap and wont go through a intruding varmint, the wall and down into your neighboors house. Also, its light recoil means anyone can learn to use it and not be afraid. magazines hold up to 100 if you get a drum.
unless your planning hand to hand combat, get a synthetic. Its light and wont rot away over the years.