An original story that was actually really novel at the time, and still remains memorable today. Music created for the game and licensed from the franchise. Fully voiced characters (something mostly not done at the time). KOTOR represented an untapped potential, which was taking a great Star Wars story and joining it with the kind of PC RPG gameplay fans had come to expect.
There were also some other releases, but primarily this was a wide open market for next generation games. Star Wars: Knights of the Old Republic released in 2003, which was a very important time for console RPGs that had only seen Final Fantasy X as well as smaller RPGs release for the PS2, and The Elder Scrolls 3: Morrowind on the Xbox for the Western side.