For me it's gotta be 3 guns:
Remington 660 in .308 (lightweight carbine, very accurate, back-up iron sights), Ruger SS 4" Police service-six in .357 (rugged, simple, versitile), and finally a SS S&W 63 4" adjustable sights in 22lr (small game getter). I believe this to be a very versitile trio, able to hunt and/or fight as the situation dictates.
Honorable mention: Colt AR-15, Bulgarian AK, Marlin 336, CZ 452 scout, remington 870