I've been a Christian since 1974. Here are some of the reasons.
More recently, I have written a leaflet intended for giving to people who are at least vaguely interested in knowing God. Here is the same text as an Openoffice document (Openoffice is a substitute for Microsoft Word which you can get free from www.openoffice.org).
Over that time I've thought a lot about the way the world is and how it and we relate to God. When I first became a Christian, I took an uncritical view of modern scientific naturalism, and thought that it was unnecessary to believe things in the bible that don't match naturalistic thought (the virgin birth of Jesus, for example). Since then, I have changed my mind about that and a lot of other things.
Here are some articles about various subjects from that point of view.