Halo. Yes, the original Xbox game is now on Windows PC, and I played it. Unfortunately my graphics card is terrible. I have an older NVIDIA graphics card, and I desperately need to update my computer.
Even with the slow graphics card, i was still able to get a decent amount of graphics... the graphics on my PC are worse than PS2! Oh well.
I tried the online multiplayer mode, and it was fun, until I kept getting killed by a bunch of guys running around the game map.
Halo is an amazing game, and it is worth the money to buy an Xbox just for this game (along with Project Gotham Racing, Rallisport Challenge, and a few other Microsoft games)! I can't wait until Halo 2 is released this November, it is going to be awesome!