I said it in the first post, and it is worth repeating here. C.S. Lewis' book "Mere Christianity" is an awesome read on this subject. Lewis was a great author, and a truly brilliant man. The subject matter covered in the book is essentially the same things that are being covered in this thread, and the book is tough to stop reading.
This thread has been enjoyable. I have been in literally hundreds of religious threads, and this one is one of a few that have actually been civil.
One question that I notice over and over again is the question of "How do you know". I will do my best to try and answer that.
I don't 100% know that there is a God or that Jesus died so that we don't have to. Jesus could have just been a guy who was a rabble rouser at a time when the Romans didn't need any more Jewish rabble rousers.
However, a little better than 10 years ago, I had I guess what you could call a "religious experience". I was in the midst of some deep introspection over a period of several weeks when it all culminated one night while having a discussion with my best friend. That night we both gave our lives to Christ. There were no clergymen or fireworks or anything like that. The only out of the ordinary experience was an overwhelming sense of peace accompanied by a feeling that I would describe as out of the ordinary. I can't adequately describe it, but it was very reassurring at the time.
I was not what I would consider at the time a "bad" guy. I didn't kill people or anything like that. But I wasn't an angel either, and I knew that, but I tried to tell myself that I wasn't that bad. In retrospect I wasn't a good guy either. I cheated on my girlfriends, I hurt people emotionally,I had no respect for anyone I, could go on, but you get the picture I think.
I wasn't really scared of the afterlife, I just started to realize that the things that I thought were so important were not really all that important. Things that I thought would fulfill me really weren't. A guy can only have so much sex, with so many different girls, and that didn't make me any happier. I did plenty of drugs/partying and no amount of drugs made me happy. No matter how big or strong I got there was no happiness there.No matter where I looked there really wasn't any real happiness to be found. At best these things would lead to momentary pleasure followed by emptiness or even regret. These were all things that led me to that night that I mentioned earlier.
I just got to a point where I realized that I wasn't going to find what I was looking for in another person, or any other material thing. If anything was going to make me feel better, or more complete, or healed, or however you want to put it, I knew that it was Jesus or nothing. So I took that step out in faith, and just said "Ok, if you are real here I am, help me".
Since then there has been numerous experiences that attest to the fact that my faith has been well placed. At one time I thought that this God stuff was all about avoiding hell, but since making that step of faith I have realized it is totally different. (at one time I also thought that God was some cosmic disciplinarian who wanted to catch me screwing up so that He could hold it against me, I know now that this is not the case at all)
Sin isn't something that pisses off God. Sin is a destructive force that actually causes pain, death, etc. Sin hurts us. You can see the results of sin if you look for it. I was hurt by my sins, and the sins of others. Jesus died so that I didn't have to bear that hurt anymore. Jesus didn't just die so that I could go to heaven, Jesus died so that my life could be better right now. That feeling of not being satisfied was because I was looking for life where there was none to be had.
I haven't had some charmed life since then, I have the same troubles as anyone else. Anyone, Christian or not, who pretends like their life is just rosy is either a liar or sheltered. It is just when my life is going bad I look to God, whereas at one point in my life I looked elsewhere.
The emotional pain that I used to carry around like a heavy backpack is not there anymore. It didn't miraculously disappear overnight. In fact I didn't even know it existed, all that I could see was the outward manifestations of the pain: anger, a short temper, and other negative emotions that I had just taken for granted as being an ingrained part of me. Once I saw it for what it was I asked God to help me, and He did. He said to anyone who is heavy laden to drop their burden and take up His yoke, that it is lite. You can't really appreciate that until you have experienced what it is like to be free from years of pain and emotional baggage.
It is in cases like this that I have witnessed the truth in the Bible in my own life. Jesus said that for whoever who thirst to come to Him. He was not talking about a physical thirst, but a yearning whether it be for love or security or what have you. And this has proven to be true.
The Bible says that "By His stripes we are healed". I can look and see how I am no longer an angry, hurt person, and see the truth in that. I could go on, but I think I have made my point.
In the course of this thread I have gotten a lot more personal than I would like to, but understand it is only to attempt and answer the question "how do you know" or "Why do you believe". I know because of what I have experienced in my own life. This is why I believe.
If at the end of the day, and I am creating my own reality or tricking myself then you know what? I am fine with that, because I am in a much better place than I was before. If when I die I am just dead, that is fine, I won't even know it. If my experience is any indicator, then when I die I am going to a much better existance to be with the One who loves me more than I can imagine.