I would have a hard time deciding between two guns.
Ruger GP100 6 inch stainless in .357 Mag, or a bolt action .22 LR rifle.
The 22 would be more versatile for hunting small game, the 357 for defense and close range hunting.
A 308 is overkill for squirrels, trust me <img src="/images/graemlins/grin.gif" alt="" />