No matter how brilliant a man, s/he can't be a good president if s/he is not God fearing. I think Sarah Palin can be a good U.S. president... By that logic, Adolf Hitler could have been a good president.
Whether someone believes in God is not really relevant to being qualified for the presidency.
(Though I would argue that the reasons someone doesn't believe in God *COULD* play a role in how a person approaches problems. I haven't believe in God a single day of my life, but I find myself more aligned with Christians on certain issues than I do with other atheists).
As for Palin, she is a stone cold moron. And this is coming from a person who is far more right-wing than Palin.