Obi-Wan Kenobi, Jedi Master. I was 5 when I saw Star Wars and "Ben" was the man who helped Luke Skywalker confirm that he was more than a moisture farmer from Tatooine. He saved him from Tusken Raiders and gave him his father's lightsaber. He used "Jedi Mind Tricks" on Storm Troopers. He hired Han Solo & Chewbacca. He taught him how to use the Force. And on the Death Star he faced off against his former pupil, Darth Vader, so that Luke and Leia could escape and Vader wouldn't know that he had a son. He sacrificed himself to keep that information from Anakin just a little longer.
It's easy for Ben to be overshadowed by Yoda, Mace Windu, Luke or Qui-Gon Jin. But if it wasn't for Old Ben, Luke wouldn't have grown to be the man the Galaxy needed him to be and he would have died right there on that battle station.
And so much of what I love about storytelling were formed the moment the words "A long time ago in a galaxy far, far way..." crawled up the screen and a Corellian Corvette was pursued by a Star Destroyer. A Corvette that needed to get a message to General Kenobi with the help of an astromech droid and a protocol droid.