There is no god or gods!

[Dranu]

I'll tailor my argument towards a more deistic god, then.

Just a natural philosophy one. Deism makes some pretty wild claims in addition to the idea of God (like non-interaction, etc).

Just to see where we are in this to give the discussion a bit of a road map as these things get chaotic after a while (correct me if you think otherwise Darkstar):
1.) We agree that God as defined as an infinite being is impossible to disprove.
2.) However, we are not in agreement that this god is anything more than just the universe, and so does not really show the typical notion of the God of natural theology is impossible to disprove. This appears to be the primary point of disagreement in this thread and topic.

Anyhow, on with the reply

The thing I find most elling is that the fundamentalists, the ones most religious, are the ones with the flimsiest defenses for god. The more you claim to know about god, the more you have to provide in evidence to support that interpretation

Indeed. Fortunately for a lot of them, the thing that matters most is what you love in life, not what you know.

if we consider the possibility that god was invented and arbitrariky defined as infinite, then this would be circular reasoning.

We don't create something simply by defining it; agreed! Definitions refer to something or they do not. If the definition can't be false then that tells us something, much like our other abstract reasoning’s do (e.g. axioms of math, etc)

I do no believe that you have given any proof that the universe cannot be infinite other than your assumption that if it were created by a god then it would be finite.

Correct, I have not. The universe may indeed be God at least on first appearances. I would say common sense may refute this idea (just for starters). If we say that there is such thing as void/vacuum in the universe, then we can say that there are places where the universe is lacking in being (namely in the void). Thus it is finite (even if infinite in kind). There are other ways of showing it, I'm sure.

How can anything be eternal? Wouldn't an infinite amount of time have had to have passed to reach this point? Wouldn't it then be impossible to be here?

Eternal things are atemporal, thus there is no passage of time. An example of an eternal thing that is really common sense and easy to think of is a truth claim. Another is a principle of math or logic. E.g. 2+2 IS 4.

The singularity could have existed for eons before the big bang. If we define the singularity as infinite, then the universe explains itself.

If it is logical to define it as infinite. I contend, as with the universe, it arguably isn't given what we know about it.

Also, the god of christianity is not actually all powerful (and definitely not loving) despite what people say.

Genesis 22:12 “Do not lay a hand on the boy,” he said. “Do not do anything to him. Now I know that you fear God, because you have not withheld from me your son, your only son.”

(bolding mine) In other words, he didn't know before. Therefore he is not omniscent. Therefore he is not infinite.

Again, this is the Christian God, and as you are right to think He to be the one true version of God , I am at this point only arguing the necessary possibility of the God of natural theology.

However, you have baited me to at least make this comment: much reference to God is done by analogy, and references to God changing have more to do with how our reception to God shifts rather than God Himself. The main point of that story, as I see it, is showing that God requires loving Him above all else (loving the Good for its own sake and above all else), that God ultimately provides the sacrifice (after all, remember what the mountain Isaac nearly dies at is thereafter named), and it is showing a prophetic prefiguring of the sacrifice of the true Isaac in Christ (wood bearing, chosen one, seed of the children of God, scape goat, up a hill, etc etc).