Looks like I'm out in the hills too much.
Smith K-22 6"
Good for all manor of small game and grouse etc.
Browning 1886 carbine,
Nice combination of easy to carry, and good power, makes a good "summer gun" for large or small varmints.
Last would depend on where I eventually lite (Interior Alaska), and how tough the local varmints end up being. It would be one of either a 1903 Springfield sporter in 35 Whelen, or the Whitworth Mauser in 375 H&H. Both can be used scoped for hunting meat, or with good iron sights for summer use.
Any would be fine for defense (I find the odds of shooting small game to be much more likely, as I do it regularly, and have never had to draw on a person "in battle"). A Smith 44 or Ruger 45 Colt would be nice for town use, or when the hands are full out in the hills, but if limited to 3, that is my choice.
I guess I'm glad I live where armed combat is rare, and regular hunting guns seem to take care of our infrequent needs for defense from hostile humans. I didn't know so many folks lived in combat zones.