I always found the comment "hell would be the absence of god and lack of meaning in life" very funny.
It's something most preachers/pastors have used as the basis of a sermon at least once.
It suggests that agnostics and atheists are already in hell, and while I can't argue, it's a very circular argument.
Why not just say "you should believe, because you don't believe". Well... you answered the question with itself.