I had addressed this point previously in a different manner, but I think it worth readdressing. A bizarre angle repeated ad nauseum from religious arguments is with regard to morality being a dictate of their faith or deity.

The immediate angle pretty much all atheists take on this point is that the person making the argument must then agree that the only thing keeping them from doing terrible deeds is their religiosity. While it is an important point, it still appeases the concept.

Meanwhile, the actual definition of morality goes unchallenged. For someone to suggest another has no moral basis, we have to know what they mean by 'moral.' At a base level, morality includes empathy -- acting in accordance with an understanding of how that action affects others. If we accept this as a characteristic of morality, the argument is self-defeating, for acting only by the tenants of an authority is not morality at all. It's not an act for the betterment of anyone else, or for what one feels is appropriate or fair. It's selfish and indignant.

Semantics are crucial. If you don't know what the words you're talking about mean in the first place, you can't possibly achieve reasonable discourse. A marvelous example of this can be seen in a recent episode of The Atheist Experience that addresses the meaning of the phrase "God exists." For as much as the claim is uttered, it's not very well defined.

If your "morality" means following commands for fear of being punished, then your use of the word morality is a completely different word than my use of the same series of letters. It is to do what is right, based on my own experience of being subjected to positive and negative experiences, and taking into account others when acting. No, it's not as simple as do this and not that.

But without religion we'd all be killing and raping each other.

Haha, that episode of The Atheist Experience is one that I recently posted on Facebook.

Have you ever heard of The Atheist Ethicist, Yoda? He's constructed a system called Desire Utilitarianism. I haven't thoroughly critiqued it, but I agree with the basis of his system with respect to desires.

Go ahead and check it out:
http://atheistethicist.blogspot.com/

Possibly. Be sure to read his articles explaining his system if you're interested.