Yeah, that's all very nice, but what about the fact that this is the first Halo on Xbox 360? Master Chief's latest (and possibly last) mission is hosting a planet's-worth of new lighting and atmospheric effects. For example, each planet will have a universal light source - the sun will actually behave like a massive ball of energy, casting shadows on everything. There'll be similar effects for reflections, so metal won't behave the same way a calm pool of water might.
Bungie's also building an atmosphere system into Halo 3. Basically, that means dirt and debris flying through the air will flitter appropriately, and any light source beating down on them will make that hazy, 'shaft of light in a dirty cave' effect.
Halo 3 is coming sometime in 2007, though no official date was announced. If you've made it this far, you'd better click on the movies tab before your friends start calling you about how hard they're going to kick everyone's ass online.
And no, Bungie didn't say anything about online play. But we'll assume it's in there.
