Are the Days in Genesis Literal 24-hour Days?

The most obvious argument here is that, according to Genesis One, the sun was not created until the fourth day. This seems, on the surface, to preclude the possibility that the first three days, or even the fourth itself, were literally 24-hour days.

It seems like this page should be much longer, but really, there is no other information upon which to make a decision here. The Hebrew word for day allows either a literal or figurative use. People determine whether or not they believe Genesis One was literal 24-hour days almost exclusively based on whether they believe the earth is old or not.