For the fans only: Two Halo 3 trailers. The first is a live action teaser called Halo 3: Arms Race, from Weta and the proposed director of the Halo movie, Neill Blomkamp. Personally, I think it looks right tasty. They have it looking the way it should - in that it looks pretty much exactly like Aliens.
The second clip is the first Halo 3 trailer from back in 2006. That music always puts a prickly chill through my scalp (especially when the trumpets and chorus come in at the end). By the seven gods I hope they release a soundtrack CD.