Christians, what is your VERY BEST arguments for the existence of God?

[theVOID]

"It is a blatantly obvious case of special pleading, ie 'everything that has a beginning has a cause, except God'"

No, it's a case of mental flatulence to consider that there is no end to the chain of causality. You're right that the best two arguments are causality and design, but I agree with Frodo, that I would like to see you try to topple them.
Either cause and effect go back in literal infinite quantities (which I forward CAN NOT exist in this reality, we can make a name for the infinite, and pretend to understand it, but it is not real in the sense that it can never happen). So it is special pleading that nothing made the universe, because it seems less likely that there is the impossibility of infinity, and slightly more likely that there is something we haven't figured out yet. you think god is impossible, but I think infinity in reality is more impossible.

And perceived design, also strong. There are a lot of factors that make life, and sentient life possible here today. It is either that they happened by chance, or by design. Either us being here now is fantastic good luck (and the further back, and smaller scale you look, it really is fantastic good) or it is not.

So we have two ideas. One is that the universe never really started, or that the thing that started the universe never really started, or that it did by chance. Then the universe built up to support billions of years of action, and million of life. Tens of thousands of years of advanced hominid life, and a few thousand years of sentience. As much as we can appreciate the beauty of the system, it is all just random. There is no reason that it ended up as such a beautiful machine.

Or, and I think more likely, there is more to the picture, if only because that world view is showing obvious flaws.

Did i ever say once that this proves an infinite regress or multi-verse theory or the while hole hypothesis? NO - My position is that we do not know, all of these explanations are thus far unprovable and offer no more substance in favor than each other. The singularity is the only one with any supporting evidence, so it requires the least amount of assumptions, and considering that space and time in our universe came from the big bang and did not exist prior in this theory the logical conclusion is it would be infinite. We know for a fact that events on the Quantum level can be uncaused, so there is also support for the idea that the singularity spontaneously lost stability because in infinity in terms of quantum mechanics, every event that can possibly happen will happen, and if only stability and non-stability are possible then they must both happen. Of course this idea isn't a certain at all, but this far it is the explanation with the most evidence supporting it, evidentiary or otherwise.

For the record, i do not claim that God can be disproved for the reason that it is an unfalsifiable hypothesis - my position is that there is no evidence for the existence of God and therefore i withhold belief and will continue to do so until the evidence presents it's self, assuming it exists at all.

So before you go arguing against a position i don't hold again you might want to carefully process what it is i actually said.