I wouldn't be so quick to lump him into any category, actually. It's naturally hard to classify someone's views by such a broad statement; he stated his belief on two points only: the existence and nature of a deity. This is why I would call it a blend of theism and agnosticism—his belief is theistic in that he believes there is something (which I take as meaning a deity of sorts) and agnostic (in a broader sense than the strictly religious meaning) in that he is unsure of it's nature.
Wikipedia apparently has an article on Agnostic theism. I should think that is the term we are looking for:
Deism, on the other hand, is somewhat narrower:An agnostic theist can also be classified as someone who believes in a god yet does not understand how God or deities work.
Originally Posted by http://www.reference.com/browse/wiki/Deism