This isn't presented as an argument, but there's an implied argument here that I've heard some of "Atheism's best" attempt to offer. Basically it boils down to: Because there are so many gods that are most certainly false, that means God doesn't exist.
This is a logically invalid argument. If there really is one true God out there, it is of logical necessity that all the gods listed here are false (excepting the true God if he is mentioned).
Presented in a syllogism, the argument goes:
Thousands of gods don't exist.
Jehovah is a god.
Therefore, Jehovah doesn't exist.
However, the conclusion doesn't follow from the premises, because we don't know everything about the category "gods."