STAR WARS :- KNIGHTS OF THE OLD REPUBLIC. I am currently playing it, so I do not know how long it takes to complete.
Otherwise, if you want an RPG that is pretty simple and easy to finish while you hold out for HL2, you might want to have a look at Anachronox
I liked this game as it did have an easy learning curve, and you can finish it in about 30 hours of play.
[EDIT]If you get Anachronox, make sure you download the patch from Planet Anchronox
. There is a magor glich on one of the movie squences that make you fall off the map.
Apart from that, it's an enjoyable game.