If for some reason you could only own one hand gun. What hand gun would that be? SNIP...
IF I could only own one, or had to sell all but one handgun, it would be my SS Springfield Armory 1911-A1 in .45 ACP. Still my EDC to this day, though I sometimes carry another platform.
Though I am currently looking for a more "modern" platform (read: "higher capacity than this beloved 104 year-old design*), my 1911 fits my hand naturally and has not jammed in the past ~350-400 rounds*.
Working on it has let me understand the innards as best as I can without owning calipers, precision gun smithing equipment, or the parts to build a 1911 from the frame up.
*Recent events (including those the media and the guy in the White House won't call acts of terrorism) have made me look for a sidearm as naturally-pointing (in my hand) as the 1911.
**I decided to change the recoil spring and then had to make sure it was broken in; only one FTE which was likely due to limp-wristing when I was trying one-handed drills with my weak hand.