I didn't read the whole thread and I'm sure every reason I'm going to list are already mentioned in a way or another.
There's a lot of reasons why I don't believe it. To be honest, I'm not sure if I ever did much. I was raised lutheran christian as its a custom here and my mother has her faith, quite free actually, religion was never pushed on me in any kind of way. It was a part of the holidays, I remember thinking about christmas when I was kid that the Jesus thing wasn't even the top priority in that, but the Finnish traditions were. It was as if we were celebrating just mid winter and jesus christ, it was just a christian overtone and everything else felt more meaningful.
I kept my childs faith until I was about fifteen years old, around that time I started to feel that the whole thing is an empty shell of spirituality, filled with empty words and thinly veiled threats of you either open wide and take jesus in or you'll head for eternal damnation. It also started to look extremely naive, everything, the story book, the stuff they preached, things they talked about. Naive. Empty. Meaningless.
I found more insight from heavy metal lyrics than the bible, oh yea, I read it. The old testament is the most vile, disgusting piece of horror I've ever read. A lot of it could be used as Cannibal Corpse lyrics and it would fit without a problem. I never understood how such a almighty, loving god would do such horrible things and allow so much suffering to happen. If the god truly was loving and almighty, I guess we would be living in a paradise. Yet that sadistic disgusting [censored] made people suffer in countless of way and I was supposed believe that this sadist god loved me enough to send down his only (Aren't we all gods chidlren??) son to die for all of us so we could be saved. Saved exactly from what? Lutherans don't have the ideology of original sin, so what the heck am I supposed to be saved from? The damnation? Hell in which I will burn for eternity unless I believe in the son of the most sadistic god in existence?
The thing is that I also experienced what SpiritTalker said about "religious" experience, I have had it also in a christian setting and pagan setting. I don't think that has to do with the titles, that is something universal about human existence that we can experience it and actively look for it too. But christianity just didn't do it for me, I'm far too sceptical, I question things, I am a rebel. Heck, in one point of view I identified more with Satan than God. Although, I think Jesus is rather interesting character, he was a rebel too. I hold new testament in hundred times more higher regard than the story book about the sadist god that is the old testament.
Then bit later on I naturally grew interested about age old Finnish beliefs and folklore. That made it rather clear that Christianity is a mess of traditions of those people who it conquered, the original stuff, what is it anyway? They always blab on about Israel and middle eastern stuff? What place does that have in the north anyway? We have such rich tradition and folklore with multitude of deities, none of which is like the sadist tormentor of his own creation like the old testament god is. My faith changed into Finnish pagan / agnostic type of thing, although I didn't practice it in any physical real world way.
The people who are into it... Holy crap what a bunch of losers! The worst possible people I've ever been in touch with are certain kind of almost fundamentalist christian types. I know, its not all of them, I know smart and super nice christians too, don't get me wrong. Just the most naive, obedient, unthinking, authority believers that I've had the questionable pleasure to know, are people of the church.
They ask for unthinking obedience, just believe, believe, don't think. No way that would work for me. Also, they always said, just pray and god will take care of the rest. Nothing good ever happened to me in my life from praying to christian god. Nobody heard me, nothing happened. Everything has happened when I did something myself. Their god never took my illnesses away, god didn't stop those morons who were bullying me, god never made me anything.
I realised I have to be my own god if I want things to happen. God(s) helps those who help themselves.
Ok then comes the BIG one. One life. That is all, only one life and then either heaven or hell. That doesn't make sense as I remember living before this life. Also, where do all the souls come from? God is just creating more and more and more? Doesn't make sense. Its already proven that energy never disappears, what is a soul, what is consciousness? It must be some form of energy, that's the only way it makes sense to me and energy does not disappear. I have never really feared my own death as if I have some subconscious knowledge that death is not an end, and even if it is, then its huge relief, absolute bliss of nothingness, no worries, no pain, no nothing. Even that is better idea than the christian weirdness about afterlife. And I don't believe in that either, I don't think we pop out of nothingness and then just cease to exist. That explanation never ring the bell with me at all and this is a big issue I have about christianity. Also heaven and hell? Eternal damnation or paradise? I don't think life is ever so black and white and so simple... There must be more to it.
Then history, nothing has ever caused so much bloodshed and suffering than big organised religions, nothing comes close. You can count also money and power as one of these major religions if you want. I don't want to have anything to do with an organisation who forced my forebears to their ideas with a sword if nothing else worked. I'm way too virtuous person to subscribe to that, it doesn't matter that the crimes are old already, it wouldn't take much for that kind of thing to star again. (Read = Islam becoming totally medieval.) Our tradition was drowned under christianity, although its stupid to hold any grudge for it, it was criminal and I don't want to keep alive a church who's past is full of darkness and death.
Whereas Finnish witchcraft was exactly what witches were for in the old times when there were no doctors and hospitals around. The most common story about a Finnish witch is that of a village healer or a wise person who knew a lot and could do amazing things to help others. That's something to look up to, something to be proud of and a thing to subscribe to. So there, holy goddess what a long post.