Half-Life 2: Third Best Game for the Original Xbox!
Half-Life 2 has some of the most advanced AI's that I have ever seen on an Xbox game. With some pretty stunning graphics. Some of the special effect are pretty awesome. Some other charactes that you'll meet as time goes by through the game are: Judith Mossman, Father Gregory, and many other people as well, most of them enemies.
Would this be a game that I'd recommend to those with the original Xbox-yes. It's an excellent shooter, with some pretty good voice acting. But if your not sure if you would really enjoy it just rent it and see for your self. It's a pretty fun and amazing game.