I think people here that don't know Halo games very well, would do well to realise Bungie design the Halo games to have large sandbox type levels with many numerous enemies on screen at once + decent AI which take up more processing power. Anyone who's played a Halo game will know this. The scope of the levels and the buildings within them are huge! Now if Bungie's vision was more like Infinity Ward and COD or Guerrilla and KZ2 with it's tightly scripted events and linear levels than I'm sure they could make prettier games. But Bungie would rather give us a 3 player Warthog to drive around in.
And for those questioning the original Xbox's graphical abilities...Doom and HL2 only came out on the Xbox as it was the only console that could handle it.
