No offense, but are we even sure that the video is claiming that bin Laden is dead? Suleiman Abu Ghaith, al-Qaeda's spokesman, has been fairly consistent in claiming that he's alive. Jihad Unspun even claims to offer an "unseen tape" to this effect. It strikes me that al-Qaeda has little reason to claim that bin Laden is dead in so graphic a fashion, especially if it's an easily disproved hoax.
With all due respect, the video shows a body with a jaw restraint similar to the type that is put on a corpse after death. I reiterate, it is my assessment that whose ever body this is ( and I personally don't think it is UBL) it is not dead, but alive. The cardinal signs of death - dark coloration,mottling, rigor, blood pooling - are not present. For whatever reasons, the video is attempting to present a living body as if it were a a dead one, and it just doesn't wash. In that regard ,it is a hoax.