I would have to say Luke. He started his Jedi training at a late age, some thing the Jedi Order frown upon. What took most Jedi to learn in a life time only took Luke a few years to accomplish. The only Jedi that I know who purposely fell to the dark side and was fully redeemed.
IMO, I always looked at Luke as the Chosen One. Without Luke, Vader never would have killed the Emperor.
There is no emotion, there is peace.
There is no ignorance, there is knowledge.
There is no passion, there is serenity.
There is no chaos, there is harmony.
There is no death, there is the Force.