This is a very tough question for a guy that owns 18, 1911s and loves them dearly. But if I could have only one pitol to last me forever it would have to be a Glock 21 in .45acp or Glock 19 in 9mm. In this senario of one gun, it would mean that TSHTF and no resuply or repurchase was possible. That senario excludes everything but Glock because they are very simple, uncomplicated, easy to work on, totally rust resistant, high capacity, light weight and a ton of other plusses. Oh it would have to have night sights too. My second choice would be a Colt Series 70 Nitex finished with all the bells and whistles. Like I said tough question.
...7th