I am an atheist but I acknowledge the possibility of some kind of deity. I was born a protestant just as randomman was, but my parents weren't strict on it in the slightest. Mostly they just had me come and listen or go into the kids room, it wasn't like they lived by the bible or anything.
Eventually we stopped going to church because of the hypocrisy of many of the people there. They would talk about acceptance and truth, etc., then talk behind people's backs and show absolute hatred for gays, lesbians, and other groups. I didn't understand this at the time, but I know that they were complete hypocrites and didn't even stop to think about it.
Once I stopped going to church, I began examining the world more and more. Reading books and the internet especially helped me expand my knowledge in ways that my school couldn't or wouldn't. I learned about how several of the things in the bible were simply not possible (Noah's flood, for example, if you take it literally.)
I was 12 when I first really started questioning the validity of Christianity and other religions based around gods. I mean really, it's no different than Greek/Roman mythology, just with subtle differences.
There's God and his angels in Christianity, there is Zeus and the lesser gods in Greek Mythology.
Mary was impregnated by God, later giving birth to Jesus, the son of god who had many powers. Zeus impregnated a woman who gave birth to Hercules, the son of the king god who had many powers.
Jesus went through many trials. Hercules went through many trials.
My point is that there has to be something to these lineups between ancient religions. Either they are all just stories, or there was a "son of god" who's story has been being passed down and changed for millennium. I find the former to be more likely.
If evidence were to come forth proving that there was a deity of some sort, then I'd believe it. At the moment though, there is no evidence that can't be easily disproven, so I don't believe in any kind of deity.