Pellet Puppy sums it up well...the story draws you in (the fact that they set it 4000 years before the films allows them a fresh start), the gameplay is a blast, and the graphics aren't hard on the eyes, either...
I've spent hours just playing Pazaak (a card game you can play and win money - almost like blackjack, only you go to 20, and cards can be played either positive or negative). Some of the members in your party will talk to you, or each other. There's plenty of side quests to add to your time, but most of them you can say "no" to if you don't feel like helping someone. The characters speak their familiar SW dialects, with subtitles at the bottom (Hutts sound like hutts, Twilek's sound like they did in the movies, etc.)
It's not perfect - but it's close. The menus do feel a bit console-ish (no drag and drop), I didn't like the turret mini-game (horizontal mouse control felt too loose), and there is the occasional bug (I've seen one so far).
But I highly recommend it...if you think you'd like an adventure game where YOU make choices, there's a strong story, fun characters, and great graphics, I'd give it a shot. Shame there's not a demo, as I really believe it would sell the game well. JOIN THE CULT OF THE KOTOR! http://www.craigarmstrong.com