I think there's a very simple answer to all of this: we're humans and therefore limited, therefore we can never know until the time of our physical deaths whether or not there is a God. We don't have the ability to know whatsoever, and no technology we can even conceive of in the future can say so or not, because let's face it, if God is infallible and omnipotent, He can hide his existence from us forever, if He so chose. See how easy that is? Still, though, without having any kind of personal experiences, I just think there's far too little we can know as mortal beings about our own planet and space and whatever other dimensions there may be that this life is the end of the line. I simply don't think there is such a thing as oblivion.