Star Wars, I love that damn setting. I enjoy pretty much every era of the game. One of the coolest aspects of Star Wars is that in each era KoTOR, Clone Wars, Rebellion and so on. Somehow the game still feels alive and very much Star Wars. For as different as each is. That in itself is an accomplishment.
It might also be because for me I knew of Star Wars Before I knew of D&D. Granted I knew of the great stories of King Arthur and Camelot was cool. But STAR WARS! Yup I was hooked since I was a kid.