I'm not very religious, but I have taken an interest in it as of late (grew up religious) and have friends that are both staunch atheists and devout Christians (no friends from other faith groups). While my Christbro has been trying his best to help me out, I just can't seem to be convinced, at least not fully. There are certain things that raise an eyebrow and seriously think (like the shroud of Turin/Eucharistic miracles), but there are other things that hinder me, primarily god interfering in anyone's personal lives (when there's so much more comparative suffering for others) and the notion of eternal life.
For the former, I've often heard that, given God operates on an infinite timescale and even those that suffer greatly in life can receive an incalculably greater compensation for that in heaven, and that makes some sense to me, but why would God interfere sometimes and not others, then? From that matter, why would God have Christ arrive (and thus truly start Christianity as a faith) at such a time where there are few surviving records (compared to now, that is) and in such a local area instead of a worldwide revelation simultaneously in different civilizations? Why interfere in a manner that results in far greater pagans/animists/etc going to hell or getting Deus Vult'd and then sent to hell?
As for eternity, that's just because it's difficult to comprehend it considering the mind is finite. But eternity in heaven sounds like it would be maddening after a while, and IIRC humans get their old bodies back after judgement, so would the mind be any more capable of handling it? When it comes to an immortal soul, reincarnation seems more plausible to me, just because you don't maintain an infinite stream of memories/awareness.