The key to what eventually convinced me to become a christian is how completely different it is from all the other religons that I had studyed. Jesus himself claimed to be the only way of salvation. Most other religons were pretty tolerant. If Jesus was a good man then why would he say something so tyrannical if it wasn't true. Also Jesus' act of sacrafice on the cross paves the way to spiritual wholeness for you. There is no list of hoops to jump through to get salvation. You just believe and receive it.
Also christianity offers one thing I never found sufficently in any other religon, empowerment. Many other religons give you examples to follow to achieve some sort of enlightment. None of them however truly give you a tool to follow those examples. In my own attempts to "be positive," or good, I failed because I am human and incapable of perfection, regardless of what those other religons say. When I recieved Christ as my savior, I recieved the Holy Spirit as my guide. Through Him I can achieve what my humaness could not. That is to me the most important thing.
Through Christ I'm saved and not of my own doing but by His sacrafice and grace alone. And through the power of His ressurection I can live anew.