Best type of armor?

[Grand Lord of Poop~]

Ok, history buffs, pour in your knowledge juices! I would like to ask everyone in these forums a question and hopefully start some discussion: what exactly is the best type of armour? remember, this includes every period of history (not quite, look at bottom of post) in terms of success, usefulness, manufacture, etc. I know a lot has to come under consideration, but generally, which one do you think?

edit: actually, make the time period before the gunpowders. but late medieval is ok too.