Ricky Gervais sums it all up

It's good intentions, isn't it? The New Testament: that's great. There's no greater virtue than forgiveness. I try to live my life on those virtues of kindness, forgiveness, do as you would be done by. I live by those rules. It always does annoy me when people say about atheists that they are amoral and heartless. The opposite is true. I'm not a good person because I want rewards in heaven. I'm not a good person because I will be punished by God. I'm a good person because I want to interact with fellow humans. Nature is more beautiful when you know it's an accident and art is more beautiful when you know that man is an accident.

What he said.

(From The Daily Telegraph, UK version, of all places)