Odd that I came by this thread because I was about to start one about how I think I could be totally and completely happy with one handgun and one rifle.
The handgun would be my 5 1/2 Ruger SBH. Very accurate with MCB Co. 240 grain LSWC be it a light load of Trail Boss or a full dose of IMR 4227. Absolutely a joy to shoot, and it is fun when you hit what you aim at every time you pull the trigger, and it being a nice looking gun helps as well. It would be a good gun for stopping dangerous animals, 2 legged threats, and for hunting. Being that it is single action would be the only downfall for defense if you were in a true gun fight, but the odds are low for that happening at this time.
Load it light to conserve on powder. Use lead bullets to save on money. You can reuse your brass forever if you load to around 800-1000 fps. Can also be loaded with shot for extermination of rodents. Actually the .44 Magnum has very few limitations in any situation from 0 to 100 yards.
The rifle would be my Marlin Model 60 which is dead eye accurate especially out to 50 yards. It would kill deer (only in survival situations; I don't break regulations, and I do not condone shooting deer with .22 LR), pigs, birds, rabbits, and squirrels for food, and I can carry 1000 rounds very easily. It is also a very good and quite defensive round if you need to sneak out of a situation. You can shoot it fast, very fast without loosing point of aim. Busting off 20 shot of .22LR in seconds at virtually the same location is a big plus, and Two legged threats need to be worried with someone who has a .22 LR, and is very familiar with it, and most who own one are. Why? Because it is cheap to shoot so you shoot it a lot more than anything else in the safe. It also has zero recoil so the fundamentals of rifle shooting are usually used/concentrated on more often instead of worrying about recoil. You actually shoot your rifle correctly which leads to better accuracy.
There is another factor. They are just plain fun to shoot. Like tonight I sold some Harley mufflers that I had swapped out the baffles in to a range owner. We talk, and I am pretty much on a first name basis with everyone at the range. So before I left I said, care if I shoot this .44 Mag I have in my bag. I was shooting 7.3 grains TB, Win Brass (loaded probably 8 times), CCI LP primers, and a 240 grain LSWC from MCB Co., and @ 25 yards I was shooting 1.5 to 2" groups offhand, and one handed at times. Low recoil, low report, and still moving around 900 fps. That is still a load that would penetrate deeply into any game or threat, and could be used to kill deer or wild hog easily within range.
I often think that a double action .44 Magnum would be nice. I will probably buy one soon. I am thinking about the S&W model that is a light weight revolver, and loading to just over .44 SPC velocities with a 200 grain lead or soft point bullet for a carry gun.
At this time I do not have an Auto Pistol in my possession. I own one, but all I have are revolvers in the house, and they have really grown on me. The feel and the accuracy of the revolver is nice, but also not having to chase brass is probably the biggest plus.
Sorry for the long post. Yes, I have thought of the one rifle one handgun gun owner before, and those would be my pick.