As I continue to try on the atheist cap for size (though I have a feeling this may cause some people to give me strange looks and curiouser thoughts), I offer you the most lucid (free) summary of Sam Harris' work The End of Faith I have yet to find. Read it hear at truthdig.
That's about the jist of the book. Other than that, the book goes into far more detail with the atrocities caused by Christianity (Inquisition, anyone?). It also goes on to describe belief in very solid philosophical and neurological detail. More importantly, in the last quarter of the book, Harris goes on to present a secular vision of ethics and spirituality and explain why these in fact would be more (not less) humane than the religion (read myth) based standards we have today.
If you're interested in the additions, please do read the book. If not, this primer should be enough to get your wheels turning.