Is God Plausible?

Photo courtesy of Quinn Dombrowski via Flickr

"If I should ever die, God forbid, let this be my epitaph:
THE ONLY PROOF HE NEEDED
FOR THE EXISTENCE OF GOD
WAS MUSIC” 
~Kurt Vonnegut

Whether or not you believe in a higher power, you've likely had discussions about God's existence. What is one line of thinking--your own or someone else's--that leads you to believe that the existence of God is plausible?

What's the most compelling argument you've heard in favor of the existence of God?