Jedi: Luke Skywalker.
Although he was wreckless and lacked much in training, he still trusted in the force enough to take on two of the most powerful Sith Lords ever. "Never, I'll never turn to the darkside. You've failed your highness. I am a Jedi, like my father before me." is one of my favorite lines, not just because he's basically telling the Emperor to bring it, but he's still trying to return Anakin to his former self.
Sith: Darth Sidious
The way he creates the clone wars is brilliant and when he becomes Emperor he is virtually unstoppable. I mean, he has all of the tools any dictator would want. An enforcer that inciteds fear like Vader does(and he's powerful) a planet destroying satellite, and an army of clone and/or storm troopers.