Ninja Gaiden 2

Awesome game where you go around killing ninjas, dragons and fiends with ninja weapons and fireballs (there are actually several different types of "ninpo"). It is the sequel to Ninja Gaiden for the Xbox (obviously), and you play as Ryu Hayabusa. It is also insanely hard and will require a lot of skill and patience, especially on Path of the Master Ninja, or even Path of the Mentor.