Knights of the old republic II: The sith lords.
Kotor II: the sith lords is the sequel to biowares award winning RPG set in the star wars universe. Now I haven't finished the first one but I can tell you that this sequel is very good, maybe not better then the first but still good. The best thing about Kotor II is the character building, from leveling up to getting new gear and choosing between the Light and Dark sides of the force it's easy to get immersed. The story is also pretty good, though it is kind of predictable, it centers around you a jedi outcast who at the beggining of the game has been cut of from the force leaving you powerless. You then meet up with a women named Kreia and she helps you get some basic skills back, from there on out you'll do a multitude of star wars type things. The combat in the game is arguably the best thing in the game, it's very tactical and early on it can be downright hard. But once you get some of the more powerful force abilities back (Lighting is the best) you will most likely be more then capable of taking all who oppose down with great ease. The one place the game really trips up is in the games Graphics/ technical performance, the game doesn't look very good, even for an Xbox game, but it also doesn't perform well, with lots of framerate issues and bugs. But the game manages to overcome alot of it's issues with it's deep character building and overall Kotor appeal. It may not be everyones cup of tea but for me it was well worth it.