Despite the fact that practically accomplishes nothing on-screen during the original trilogy (seriously go back and count all of the scenes in which Boba Fett actually does anything cool, you'll be surprised) he's still one of the most enduring character's in the entire franchise. So much so, that according to the extended universe he escaped from the belly of the Sarlaac thanks to a metric ton of bullshit, before promptly being captured by a bunch of Jawas, because even in stories specifically written to talk about how great he is, Boba Fett can't catch a break. But hey, his armor sure is cool.
Obi-Wan Kenobi is like the kindly grandfather figure of the original trilogy, he's the guy who gently, but firmly nudges Luke Skywalker down the path of a Jedi warrior, eventually helping mould him into one of the finest warriors the galaxy has ever seen. That's not to say Kenobi was any sort of a slouch when it came to personally doling out backhands as he saw fit. In the prequel trilogy Kenobi bests every person he fights before literally cutting his own student down to size. When Darth Vader tried to repay the favour decades later in the original trilogy, Kenobi chose to become one with the force at the very last second, forever robbing Vader of the satisfaction of victory and proving that he'd had the upper-hand all along.
Yoda is hobbling proof that size doesn't matter, literally one of the first things we ever saw him do in the original trilogy was effortlessly lift an X-wing into the air just to show that he could and during the prequel trilogy he only seems capable of moving via sick backflip. And this was when the guy was like 900 years old, can you imagine what Yoda must have been capable of when he was in his prime? I'd bet my left nut that the only reason they haven't made a prequel movie starring Yoda is because the entire thing would need to be shot while travelling at Mach 3.
It says a lot about a character when the thing most people argue about isn't who you'd be able to beat in a fight, but whether or not you shot someone first. The "Han shot first" argument perfectly encapsulates what makes Han so awesome. He either shot Greedo first, which would make him a rebellious, quick thinking badass, or he sat and allowed Greedo to shoot at him without flinching before returning fire like a badass. Either way, Han comes out on top and wins, because Han Solo always wins. Han Solo does whatever the hell he wants and still comes out on top, he smack talks some of the most dangerous men in the universe and comes out of it slicker than an oiled snake. He dicks around constantly and still gets the girl and a medal and he's not even the main character. Luke Skywalker may have been the hero of Star Wars, but Han Solo was the guy we all wanted to be.
Of course you guys voted for Darth Vader as the best Star Wars character of all time, because he's objectively the best thing to come out of the entire franchise. He's so intrinsically intimidating that dubbing him in German makes him sound less aggressive. He's so cool that the chemical symbol for the stuff that makes up the other side of your pillow is an anagram of his name. He's not just a movie villain, he's the movie villain, he's the measuring stick against which all other movie villains are judged and they all come up short because he's Darth f*****g Vader. Vader didn't take the top spot on this list, it was willingly handed to him because to be fair, no one else deserves it more.