Damn I have always loved the Halo series, and now it looks like I am going to have to buy an Xbox 360 as Halo 3 has just been announced with a teaser video and slated for release in 2007.
http://www.bungie.net/News/TopStory.aspx?link=Halo3Announcement
And if you check out the videos, they have declared that everything is being rendered on the Xbox 360 in real time.
The videos show some clue to the story line so watch closely.