I really enjoyed Sam Harris' first book The End of Faith, at least until he slipped away sounding like a crypto-Buddhist in the closing chapters (an issue he has since clarified to my satisfaction). I did not read his brief Letter to a Christian Nation but have learned the gist of it from a variety of presentations Harris made during his book tour for that slim volume. He has a new book coming out, The Moral Landscape: How Science Can Determine Human Values, which appears to expand on ideas he discussed in a recent TED talk.
In 2007 Harris gave a very interesting lecture at the Atheist Alliance conference title "The Problem with Atheism," in which he questioned the self-applied label of "atheist," equating it to the nonsensical labels "non-astrologer" or "non-racist."
"We should not call ourselves 'atheists.' We should not call ourselves 'secularists." We should not call ourselves 'humanists,' or 'secular humanists,' or 'naturalists,' or 'skeptics,' or 'rationalists,' or 'freethinkers,' or 'brights.' We should not call ourselves anything...we should be decent, responsible people who destroy bad ideas wherever we find them."
Harris has taken much abuse and suffered some disavowal from the hard core atheist community but takes advantage of such opportunities to express his views further and with greater clarity in a variety of essays.
His views impact an idea I hope to write on one of these days. Until then there's much to read and watch at his website.