Doom isn't adored for its story so I can't see the point of a movie - or one of Halo for that matter. It certainly looks awful and not very Doom-y from the pic I've seen.
What are these people thinking? "Hey, gamers enjoy pretending to shoot things for hours on end so they're bound to enjoy watching someone else doing the same and having all the fun" Will Hollywood never learn?
If they do Half Life (god forbid), I nominate Ryan ReynolRAB or Ed Norton for Gordon.