
If you've been keeping tabs on Hyperspace's ongoing polls on favorite characters and favorite quotes you'd have noticed--as the folks at the fan club have--that Obi-Wan Kenobi's popularity among fans has gone up exponentially. Going by the rather unscientific fan club polls, Obi-Wan had the most favorite quotes from the saga and won every poll on favorite character from each prequel film. His older persona Ben Kenobi even went up a few notches in ANH. Compare this to a poll the Star Wars Insider ran in 1998...ol' Ben ranked up there but not that high. Boba Fett got more votes than he did.
When AFI had its list of 100 Heroes and Villains in 2003, Luke was shamefully kept off the list (as was Leia) but looked who ranked at #15...Obi-Wan.
You don't have to be a rocket scientist to figure out the prequels have boosted Obi Love considerably. Before then, Obi-Wan had his fans but he was regarded as more of a second-tier character. The fans focused more on Luke, Han, Leia, and Vader. In fact I knew many Luke fans who loathed Obi-Wan because they regarded him as a lying, manipulative geezer who tried to use Luke as a tool of revenge against Anakin/Vader. No word on whether this perspective changed post-ROTS

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Obviously, having Obi-Wan at the forefront of the prequels helped his popularity. For the first time, we get to see him in his prime, doing all of the heroic stuff we'd wondered about when we saw Luke get all gushy over Ben fighting in the Clone Wars. Young Obi-Wan represents everything we thought the Jedi were supposed to be and everything we thought they believed in. The guy is a true believer in the Code, the Republic's ideals, Mom, apple pie, and lightsabers raised in the defense of the innocent. People love that.
But I also happen to think it has a lot to do with Ewan's appeal as a performer. He could play a serial killer and you'd still find some reason to like him. Even as an amoral junkie in Trainspotting, he was the most likeable character in the movie. Yeah, even more than Spud. He's a charmer. He's also hot. Not in the same way Hayden is, but he's a handsome fella in his own right with a great sense of humor. Even if he were uglier than a toad, I'd marry a guy who makes me crack up as much as Ewan does in some of his interviews. He seems rather uninhibited too, which is alluring. Aside from that, Ewan had the very difficult and scary task of stepping into a role made famous by a much-venerated actor and he pulled it off beautifully. Not only did he more than adequately fill those shoes, he made the younger incarnation of Obi-Wan his own.
Personally, I think Obi-Wan is one of the more complex characters in the saga. In my estimation he's basically a good fellow with flaws and misjudgments. You can see the moment in ROTS when he closes his heart off to Anakin and it's just as infuriating as it is heartbreaking. In ANH, Obi-Wan has become a Gandalf, an Allanon (from the Shannara series of books). He's a man who fights for good but still has his own agenda based on what happened in the past. He's not St. Obi the Blameless, but he's not on par with Palpatine either.
I don't know how fans will regard Obi-Wan 20 years from now, but it appears Lucas along with two fine actors have crafted a memorable, thought-provoking hero.