@RexRed,
This is a typical materialist answer, Rex. Nice try, but what gives you the impression that if God exists He would be material, and therefore must be very complex and have a huge brain?
If God does exist (and I believe that He does), then he cannot be material, because God would Himself be the creator of all things material. He therefore must be other than material
But here's my argument for why God must exist. It's actually a very ancient cosmological argument.
God by definition would be the all powerful creator of the universe (defined as everything that ever began to exist).
Everything that begins to exist has a cause.
The universe began to exist.
The universe therefore had a cause.
In order to solve the problem (actually a logical absurdity) of an infinite regress of causes, we are forced to posit a necessary first cause to the universe, that itself was not caused. In other words, an entity that has the power, knowledge and ability to cause the universe to exist, but at the same time cannot be a part of what it caused. It therefore must be eternally existing.
That in essence is God; the necessary (out of pain of absurdity) first cause of everything that began to exist in the universe. It'then absurd to suggest that God, if He exists must somehow be complex, have evolved, and have an immense brain.
God is necessary. I would go so far as to say that on first principles of reason, God's existence is self-evident, and that atheism in all of its forms is rationally untenable. But that's another discussion.