John Moses Browning uber alles!
The Mauser boys run a respectably well played and very close second.
Diudonne Saive for his heavenly FAL closes the ranks in third place despite his weird, phlegmishly foreign name.
John C. Garand gets an honorable mention for winning WWII...
Kalashnikov gets my vote for "Most Accomplished Plagiarist", after taking a novel German design and cheapening it up quite a bit, thereby making it more peasant proof. Had the Germans fared a bit better in the late unpleasantness, we would all be toting Sturmgewehrs.
Eugene Stoner gets my vote for most contrived, overdesigned, ridiculous POS ever sold to the US Military.
Unless of course, the US Army actually ends up buying the bill of goods packaged as the OICW (Offensively Idiotic Combat Widget), in which case Eugene only gets dishonorable mention and a smack in the mouth.
As a side note, I know someone that has an uncle that dated JMB's daughter way back when. Evidently she was quite the package.