Grand Admiral Thrawn without a doubt. That guy is insanely awesome.
But if canon only... I can't pick. Too many I love. Lando, chewie, wicket, han, yoda, jar jar binks, boba fett, salacious crumb, vader, mace windu, obi wan are all in my tops. And only three of those are a joke!
Seriously though vader is basically star wars and star wars is vader. The first 3 episodes are his origin and fall, the last 3 are his redemption story. His fall and redemption is the central theme to everything star wars. I wonder if this is going to change with episodes 8, 9 and so on. In 7 vader was still very much present, as he seemed to still have a grip on kylo ren and drive that story forward. So we'll see if vader's footprint is still on everything.
Yoda, how can you not love yoda? And we still have no origin story for him which makes him all that much more mysterious.
Then you have typical badasses like chewie, lando, boba fett and mace windu. They're all really cool for similar reasons. Han breathes life into the original trilogy, without his humor and snark those movies would be very flat. Obi wan is just a cool character, transitioning from a padawan into a jedi master and being so central to the vader plotline. The end of episode 3 when he's screaming at anakin you were supposed to bring balance to the force not destroy it! is bonechilling.
