Being a Christian doesn't mean you go to church. As Jesus taught (who was actually Jewish by the way), the most important things are to "love your God," and "love your neighbor as yourself." Those are the main two tenets of Christianity.
Wow, aren't you the "all-knowing" one. Anyone who has an ounce of sense realizes that no one knows the truth behind this universe, including the most brilliant of scientists. It's fine not to believe in a god or religions, but it's foolish to completely reject other people's beliefs.
Osama? The U.S. government is responsible for killing far more people than Osama Bin Laden ever did. Who supplied him with weapons in the first place? The United States. Who killed hundreds of thousands of civilians in Iraq? The United States. 'Nuff said.