I went from agnostic to atheist when I realized that the only way to get to a god that could possibly exist and fit the observable evidence would have to be so watered down that there would be no reason to call such an entity "god."
God is certainly not necessary to explain anything. Even if some entity exists that kicked off our universe, he did little more to earn the title of god than Jacques Clouseau did to earn the title inspector. What's the point in having a god that deserves neither worship, nor respect?
When you add it all up, an absentee god is equivalent to no god. Since no god seems to be much more likely (not to mention the more useful and intellectually honest theory) what's the point in jumping through hoops just to say that god might exist?