I havn't given up on the possiblity of an impersonal, intelligent designer of some sort (whether aliens or a 'God', who knows) that is presently beyond our comprehension or ability to discover. So I've moved from being a confident believer to a much less confident one....now more of a Deist/agnostic I guess.
I gave up on the concept of a traditional, personal, prayer-answering God as revealed in ancient scripture because there are no theodicies (defences/excuses for why God permits evil and suffering) that stand up to rational scrutiny and no satisfying reasons for why a God with anything resembling our own standards of morality and conscience would remain so utterly aloof and hidden.
It seems that religious faith is more incredulity than anything else.