I see allegations that Bush said that God told him "to end the tyranny in Iraq". Most recently, it popped up in /r/atheism (warning: NSFW link) to support a rather dumb argument of "Bush was a theist, therefore I will never vote for a theist".
Putting aside the stupidity of this argument (which, as the top-most-voted comment points out, amounts to "I'll never ever vote"), consider the likelihood of this quote actually being said by Bush: the only source that can be found for it is a single Palestinian official. Let's be honest - the Palestinian government, whether or not you agree with Israel's actions, would likely have an axe to grind with the U.S. government.
The fact that the U.S. government did not try to deny it, while relevant to the argument for the quote's accuracy, is immaterial when faced with the fact that there is not a single additional shred of corroborating evidence - no other (more) reliable witnesses, no transcripts, no recordings - nada.
So, folks, let's put this one to bed, like we should do with that oft-repeated Thomas Jefferson quote. It wouldn't surprise me if Bush thought that he was doing God's work (though, as Penn Jillette tells it, Bill Clinton was the most religious of all U.S. presidents), but let's not let ourselves fail as skeptics simply because doing so makes it more convenient for the argument at hand - a short-term gain for a long-term loss of credibility.