Not really a rebuttal to the other thread, maybe it could be taken as such. So why are you a Christian? Here's what I believe
From the most simple outlook, Christianity answers three very important questions, all posed by a guy named Gauguin. These questions are as follows:
"Where do we come from", "What are we", and "where are we going".
The Christian, the Jew, and the Muslim would all answer almost precisely the same way, that "We come from God, our creator. We are human beings made in the image of God, our creator. And when we die, we shall be judged by God, who wants us to spend eternity with Him.
We get three out of three in Christianity. I would be immediately skeptical of any religion which did not sufficiently answer those three questions. This is how I know that Zeus, and the entirety of the Greek pantheon, are probably insufficient as far as possible Gods are concerned: they couldn't give such a comprehensive answer. Zeus, Odin, ect. cannot be the ultimate explanation for all of reality. Most of these gods would get a Gauguin score of zero.
There's that, and I've studied enough philosophy and have read enough theology to know that Christianity is the most reasonable religion around. Additionally, I am waiting, from a purely anecdotal perspective, to see the fruits born of my faith, and I think they will do quite a bit to reassure me about the validity of my belief.