There is quite a difference in detail and lighting going from Halo to Halo 2 and finally to Halo 3.
I didn't realize it was that big. The people saying, "Just Halo 2 in HD" are grossly overlooking the differences.
HD Version: http://www.gametrailers.com/player/25482.html?type=
Threads of Interest:
The Movie Thread: http://www.vgchartz.com/forum/thread.php?id=6880
The Crow Eating Thread: http://www.vgchartz.com/forum/thread.php?start=0&id=3886
The Betting Thread: http://www.vgchartz.com/forum/thread.php?start=0&id=7104
Custom GIFs Thread: http://www.vgchartz.com/forum/thread.php?id=18963
The Greatest Game Ever Conceived On Any Platform
Tag: "I have tasted Obi-Wan's bitter tears"