"If god or gods do NOT make their presence known to men (or at least the priests who make that claim who then convince others based on faith) then there would be no religion. Period."
Darwyn, it is interesting you should say that, because, conversely, since there IS religion, God must exist (else he could not make himself known to man.)
As far as that all goes, God does make himself known, but not in a ridiculously conspicuous type of way of which atheists like Carl Sagan love to point out the absence. It has been said, but I don't think it has been elaborated on enough. For instance, for God to give every newborn a sort of "introductory" lecture about himself, or for him to place a giant banner in the sky saying "I am God and I am real," or any other grandiose means of making himself known, while fully capable of doing so, would go against his entire purpose for making everything in the first place. To be sure, he could do it, but it would make us little more than automatons. Instead he is much more humble about it. Read Christian literature for just a few minutes and you'll hear about how "humble" Christ was to come in the way he did. He could have just taken over the world, and the Jews would've been like "Yeah, freakin' awesome!" But the rest of the world would become puppets, or slaves, or robots, or insert any non-human enitity here. Instead, the message was carefully crafted to be one of choice, believable, but doubtable also.