For The Existence Of God. Either God exists or He doesn't. If God doesn't exist then there are three things that are true. Even if you argued that there is significance in your life such as the enjoyment of doing anything you want, it would not be the Ultimate significance because everyone who has lived or will live in the future will eventually end up in the grave. Even if reincarnation exists everyone will still die and become nothing because the world is slowly deteriorating down to nothing itself.
Life has no value.
Everthing is permissible. There is no such thing as right and wrong because there is no all knowing and all powerful Creator to define what is good and what is bad. It becomes society who tries to define it. What does that matter though if the people making laws define right from wrong. They are just as human as any other person in the world.