Welcome to 3 guys sitting on bar stools, you've asked your question, now you'll get 5 different answers from 3 guys.
I would recommend investing in a 12 gauge pump shotgun, a Remy 870. I would also recommend investing in either a bolt action rifle chambered in .308, such as a Remy 700 SPS, or an AR chambered in .308 such as FnH's SCAR 17H.
Before putting anything downrange definitely walk the perimeter of your property to learn what lies beyond your property line.
Also, don't discount a .22LR rifle, such as a Ruger Takedown in .22LR, for varmints and plinking.
