Well, I'm an atheist. I can't say what I will believe 30 years from today, but I can't imagine how this will ever change. The word 'god', the concepts 'god' and 'worship' are absolutely, completely, unequivocally meaningless to me.
More below, and no, I'm not trashing Religion.
Richard Dawkins coined the word 'meme' to describe Religion, the evolved social structure. He says a meme is a selfish thing, exists only to propagate itself, and is inescapably cruel and selfish in enslaving and destroying men for its own senseless goals. Bertrand Russell said that the only good Religion has ever done for man is to fix the calendar. Until recently, I was inclined to agree with both, though I recognized that the personal 'feelings' and 'conviction' that draws men to Religion are real mental events, and not insanity, dishonesty or mental laziness.
But an honest look at human evolution paired with the evolution of Religion does not allow me to agree with either Dawkins or Russell. There is a symbiosis between human sociability and civilization, and Religion. It is simply not possible for humanity to have carried such a large, demanding monkey on its back for the last 35,000 years, it is not possible for Religion to have remained in place in every single culture on the planet, without accepting that Religion did fulfill a human need, and was perhaps indispensable to the formation of a civilization. Notice that I say 'Religion', not 'god'. Many cultures did just fine without any notion of 'god', the 'higher/est power'.
My present view is this: the human psyche does have a dark side. I trace this dark side to ambush hunting in primitive man, the cocaine-like rush of stalking and killing. This mental process cannot be ignored, if it is there and if it is discovered. Religion is the way in which humanity harnessed this force, diverted it from its original psychotic murdering nature into a socially acceptable (and sometimes even constructive) outlet. In this sense, 'sin' really did enter the world.
'God's' words to Cain really do make sense ("If thou doest well, shalt thou not be accepted? and if thou doest not well, sin lieth at the door. And unto thee shall be his desire, and thou shalt rule over him." --Gen 4:7). The coupling of Religion with the sacrifice of animals in the earliest religious traditions (Abrahamic and Vedic) also make sense. It is 'morally' OK to expend this energy stalking and killing animals - but not humans.
So yes, I am now prepared to admit that Religion really did 'invent' morality, or should I say as we invented civilization, our first attempts to define morality were expressed in a religious language because that was the only way we knew to communicate morality. From there, the evolution of family, tribal, state and king-gods was inevitable, as civilization followed these paths. Where I take exception is in the creation of the 'afterlife' and 'immortal souls'. The Greeks did us a great disservice, and Religion has not been truly adaptive since then.