Agnosticism - I do not know if God or gods exist.
Atheism - I do know, God or gods do not exist.
Theism - I do know, God or gods do exist.
Polytheism - Many gods exist.
Henotheism - The henotheist worships only one of the many gods who exist.
Monotheism - Only one God exists.
Pantheism - All things that exist are part of God. Therefore God is impersonal.
Deism - The one God who exists is personal, yet He is not involved with humanity.
Personal Theism - The one personal God is intimately involved with humanity.
Unitarianism - God is only one person.
Trinitarianism - The one God who exists, is, by nature, a Trinity - three distinct persons within the nature of the one God.
We also discovered that:
This may seem like quibbling but it really isn't. As an avid fan of Star Trek, let us say (for the sake of argument, of course) that I am firmly convinced in the existence of the planet Vulcan. Though you cannot prove the non-existence of Vulcan, you would naturally doubt its existence because of the absence of concrete evidence, and you certainly would not base your worldview or your actions on the assumption of its existence.
All I can say is, thank God I'm an atheist! :-)