I personally think Bush is way to stupid to be the anti-Christ. (if such a mythical figure really does exist).
Of course, along with Rumsfeld, Cheney and Ashcroft he could be one of the four horsemen of the Apocalypse.... (with the other 3 stooges supplying the brain power and Bush being the token village idiot of the group... sort of the same position he currently fills in Washington)