Monkey D. Luffy. He's an idiot. He's also a glutton, childish, gullible, and did I mention he's an idiot?
But Luffy not only has bad habits and personality traits. He also has good things about him.
Luffy is a genius in battle, able to come up with brand new moves on the spot. Not only that, but he had a whole lot of moves, he created before the start of the series. He's even able to incorporate attacks of his enemies into new moves or forms.
Then, there are the gears, which helped him reach a whole new level, and increase the potential each of his moves has.
Two years later, Luffy has incorporated Haki to his arsenal. His moves have evolved into brand new ones with the help of Armaments Haki. We've yet to see all the moves Luffy has created during his training, so all we can do is keep reading the manga and find out!