It really depends on what you do, where you live, etc. Are you a person that hunts, one that shoots at indoor ranges only, one that has accessibility to land to shoot on, etc? What are your preferences in firearm types? Military, civilian, sporting, ect?
With that said, I would list the following:
Handguns:
~Browning High Power
~Quality SA .45 cal. 1911
~Compact Service Pistol in .9mm, .40 S&W or .357 Sig (Spriger XD, Glock, HK)
~Small Frame Revolver in .357 Mag with 2 1/2 - 3" bbl
~MKII or Buck Mark .22
Rifles:
~Carbine in .30 cal. Or, a PC9 or PC40 from Ruger
~Scoped Bolt Action in .308 or .30-06
~Lever Gun in .44 Mag
~M1A
Shotguns:
~Coach Gun
~20 Ga. 22" - 24" Semi Auto bird gun
~Mossy 12 Ga. HD gun Or, HK Tactical Self Loader (my favorite)
~12 Ga Semi Auto 3" - 3 1/2" w/26" bbl and Invector chokes
OH, everybody needs a Pellet Gun!
~Benjamin/Sheridan 5mm pump