A better analogy would be as follows: "Why don't you believe the sun is composed primarily of hydrogen and helium?" "Well, there have been hundreds of theories

A better analogy would be as follows: "Why don't you believe the sun is composed primarily of hydrogen and helium?" "Well, there have been hundreds of theories of what the sun might be composed of; giant birds, fire, holes in the sky... I just believe one less than you do" That analogy still only works if there's some particularly good reason for believing that one God is significantly more likely to exist than any other.