One objection to the cliche' that atheists believe in just one fewer God than religious believers do, was expressed recently over at Christian Cadre:
Third, there aren't really thousands of other gods that are taken seriously, and anyone who sees religions as the same except that they have "different gods" has a very childish grasp religious belief. Sure, a thousand and more years ago some people believed in Ishtar and Odin and Zeus, but only a handful of people (if any) really give those types of religions credence today because, unlike Christianity, they don't ring true.
The truth is that every God that people have believed in, both in the present and in the past, was taken very seriously by those very people. Just because we no longer take most of them seriously doesn't mean we could ever have convinced them otherwise via an argument, or with counter-evidence. Christians simply take their God seriously, and that's what all other people have done too.
There is only one God that is deserving of the name, and that is the philosopher's God. That is the God established by reasonable arguments, if such a thing can be done. The other Gods are human religions based upon the doctrines of a superstitious "faith," that legitimize and grant power to those who propogate them, which are spread by the sword, but not containing much by way of convincing evidence, in my opinion.