Only one pistol? Browning High-Power 9MM, hands down. The last gun John Browning designed, and representative of his years of experience and genius. Yes, I know another Belgium gunsmith had to finalize due to John's death....but this is pistol perfection in every sense of the word. Clearly the one you want on a desert island. I love my revolvers (629 and model 15 among my favorites ), 1911's and polymer guns (Walther P99 and PPS in particular); but the Browning is in a class by itself. Going strong since 1935, and still the choice of sidearm for many military's, police departments...and even Special Force units around the world.