Well, I think George Carlin says it best: Religion is bullsh*t
Worshiping the sun seems like a rational idea to me too. (:
No, seriously, I can't get myself to believe in god. First of all, why must it be christianity? I don't get why I should believe in that one while there are so many other religions to believe in. To believe in something which I do not completely agree with or understand seems illogical to me and is just something I would not do. By that, I do not mean the stories in the bible, for some of them might be real but over the thousands of years they got distorted, misinterpreted and exaggerated, as Scourge already said. I rather refer to homosexuality, contraception and such.
Of course it's all faith. But there are so many things around christianity and so many controversies that I can't get myself to believe in this. Although it is a nice idea and it sure can be consoling from time to time. If it helps you to become a better person, there's no problem behind it.
It is not like I completely deny the existence of some higher being (am I being agnostic? well, that's fine with me), it is just that I can't identify myself with that whole bible and repenting thing. Repenting is for me just something you do in order to feel better afterwards ... To just kick away that one sin, to salve one's conscience and say: "Perfect, everything is fine now, I don't have to care about it anymore. If it happens again, I'll just repent again."
And from an impartial point of view Mao has a point in his saying that if someone is religious, he should understand that all those religions are not compatible with each other. (Whatever that person might do then.) They believe in different gods and deny the existence of other gods which do not fit in their persuasion. So how can they coexist? Although it is not possible to evaluate which one is right and which isn't ... No one can do this.