Sith. I like being evil in many games. And seeing with the fandom of Star Wars, some who choose the Republic will be massive haters of the Sith. Not like they hate the players, but they hate the Siths of the franchise. The contrast between Republic and Empire sets you in a rather patriotic mindset, and just because many love Star Wars so much, it will be much like "For the glory of X and Y!".
And I like that, it adds to the immersion of the Star Wars universe. And I also like being the big enemy in those games. The reason I hate to be evil in other games is because the silly viciousness of the bad guys. With Star Wars, it's different. Sure, the Sith want to rule the entire universe and all our apple pies, but it's made better than in games, mostly cause it didn't start out as a game. It started out as being a medium for storytelling, and the movies nailed the way to emphasize the evil of the Sith.