Now while I know Princess Leia, Han Solo, and Chewie should rightfully be first in line for this sort of argument, let's not forget this guy.
Knights of the Old Republic had plenty of great characters, but nothing came remotely close to the panache and humour displayed by the assassin droid and Jedi hunter HK-47. Built by Revan, HK-47 is introduced to the player as a droid that is "wasted in a shop or translating for some moisture farmer".
From there, HK-47 becomes one of the game's funniest characters. Disney's wiping of the collective Star Wars slate has meant the robotic quips are no longer canon, although fortunately there's always The Old Republic to keep the memory alive.
How good would another KOTOR be?
But, best Star Wars character. Which one is your favourite?