Best military hardware..
That's a real difficult question to answer.
There are lot of different great hardware in different categories..
If I must pick one from your list I would say the AK-47.
Since it was introduced to the Soviet Army in 1949, about 50 million (30-50mill...) copies and variations has been produced all over the world..
Making it the most widely used in the world..
It's not very accurate, but it does almost always work under any condition, and it's real easy to maintain.
I've seen several of these in Lebanon, and I'm impressed by the simplicity of the weapon!
The Russians has been real good at following the KISS principle..
(Keep It Simple Stupid..)