Bungie has put forth a video talking about
Halo: Reach and how it's different from the past games. The new game focuses on a group of Spartans and all before the events of Master Chief's arrival. It also shows the improvements done to the graphics and I have to admit, it does look a lot better. You get to see a lot of the work in progress so there's a chance it'll look even better when the game finally ships later this year.