About the Anniversary edition, I'd like to add that not only did the original graphics suit the tone more, I'd argue it's effects were better as well. Ever since Halo 2, the special effects have gotten more glittery, and it's less imposing because of it. Compare the Hunters Fuel Rod guns, or the grenade explosions in Halo 1 to Halo 2.
Halo Reach did a lot to try and recapture that old feeling though. Everything had much more impact to it then in Halo 3.