I wasn't a big fan of Star Wars until I first played this game. I watched the movies of course, but this game offered a fresh perspective on the setting, placing the story 3000 years before the movies. Basically, without giving out too much of the story: what if Luke Skywalker and Han Solo were the same person, Vader and Leia weren't related to each other and to him/her, and Leia was a Jedi? Also, there is a big reveal, which *isn't* about anyone being anyone's father.
This game was perhaps the best (old) Bioware's RPG, a veritable crème de la crème, at least shoulder-to-shoulder with Baldur's Gate and Mass Effect. The similarities to those other games show through and through. You can play this game either as follower of the Light Side or Dark Side. Playing the game as LS is very satisfying. Unfortunately, one of the weaker points of this game is that if you go Dark Side, you will not be roleplaying as someone like the sinister, plotting Emperor Palpatine, but rather an unsophisticated brute.
The actual DnD-like mechanics of the game aren't ideal, and there are a couple of "optimal builds" for a warrior, wizard and rogue archetype, but in my opinion that is secondary to story. If you are an RPG fan, and haven't already played KotOR, I recommend doing that!