OK, so the original question was "If you could only have 3 "FIREARMS" [emphasis added] for the rest of your life, what would they be (and what caliber) and why?"
Well, I would do the following
1. Blaser R-8 or R-93 with multiple barrels is different calibers to cover everything from small game (.223) to Big Stuff (.375). Probably a .223, .270. 308, 30-06, 300Win, 375H&H. Since the extra barrels are not considered "firearms" I think I am good with this choice. Saurer and other multi-barrel rifles are also a good choice.
2. Good Quality 12 Gauge O/U (Krieghoff, Blaser, Browning, Perazzi, etc...) with a good set of Briely Tubes. The tube will bring me down to 20, 28 and 410. This will cover all birds, give me overlap in the small game and allow for sporting clays, skeet and Trap.
3. While you can never go wrong with the 1911, I would probable go with a good 9mm (M&P, Springfield, Glock etc) Good f0r two leg protection and can use for game in a pinch. On second thought, a Sig would be a good choice because you can also change calibers (9, 40, 45) with the one pistol.
I know I am cheating by using multi barrel "Firearms", but if the ATF doesn't consider barrels or tube "firearms" why should I. Plus, if you're not cheating, you're not trying.