I was recently at a dinner party where I was seated next to an ex-pastor. I had a very pleasant conversation with him. He recently had a bad experience with church (thus his EX-ness).
I actually wish that every religious person would be wounded by their fellowship. I know that sounds awfully hostile of me, but I have found it leaves such people much less enamored with the us/them dichotomy that religious circles tend to foster. When that happens, they are so much more... real.
As such, when I spoke with him, he did not seem put off by my Atheism. Nor did I get the sense that he felt an obligation to evangelize me. We just talked.
He did have a few questions though. Since they were asked sincerely, I answered them sincerely.
One thing he was curious about was my morality. If all I had to live for was this life, why be moral? Why not do whatever I wanted? This is a common question among believers. Many believers expect a life of rampant debauchery to develop if one is without faith. I have a few friends who left their faith around the same time I did - and we all still love our wives and children, do good jobs at work, and are upstanding members of our community. :)
I can only speak for me, but I don't think a deity is needed for morality. In fact, I think a belief in a deity often hobbles morality and ethical development.
For me, right and wrong, good and bad, can be arrived at by thinking how my actions affect those around me. Does what I do or say cause harm, or does it bring life? Does it build up, or tear down? Empathy is key and no deity needs to be involved with that.
I have also found that, since leaving the faith, my ethical actions have become much more clear. When I was a believer, there were always varied layers of guilt and ulterior motives guiding my actions - it was hard to find my real self under all that mess. Now I do good things BECAUSE they are good. I avoid bad things BECAUSE they are bad... not because I am in fear of some cosmic retribution.
Believers often struggle with morality because they rarely get a chance to develop an ethic on a clear playing field - theirs is very cluttered. Take something as straightforward as genocide... wrong right? Not for the believer. The believer doesn't get to define that as wrong because they have to leave wiggle room for all the times their god did it. Yes, it is bad...but ... not... always..... The Christian scriptures are rife with bad that has to be redefined as good in order to leave the deity blameless. You do that long enough and you start to lose track of which way is up.
Also, many believers defer ethical development for simple obedience. By never making ethical choices, they never flex their ethical muscles. For example, I once heard Mark Driscoll (a hell-fire-and brimstone pastor) say during a sermon, "No hell? If there is no hell.... well, then I am going to the strip club tonight!" Since his faith deems strip-clubs a no-no, he doesn't go; but his only reason for not going is a fear of cosmic punishment. He has never worked out ethically, for himself, whether he should go or not. He has out-sourced his ethical decision making process and in doing so has caused his ethical base to atrophy. Mark Driscoll probably considers himself a deeply moral man, but I would argue that his morals are built on sand.
In the end, if this is all I have, my life becomes MORE precious. My decisions are more pertinent. What I do matters - for my wife, children, friends, community, students. I have no guarantees, so I need to make what I do count.