A few nominated the 1911. Good to see it here since it's the watermark by which all others are judged. I noticed that the Ruger is nominated and that should be b/c of its investment casted construction. The Glock is in there but it isn't the first tupperware gun (HK VP70 is) but it was Glock and the timing that made it the player it is today. The Broomhandle (C96) Mauser has been nominated. That is good as it is the first successful semi-automatic pistol and secondly, the first handgun with a staggered magazine.
OK, since a lot of the good ones are taken, here's mine: Liberator. Yep, that cheap crudely stamped out POS that none of us would shuck out big bucks for. But it goes to prove a point. It doesn't take much to make a gun cheaply and if all our guns are taken from us, we have a pattern.