A shamless plug for my old thread that didn't seem to take off.
Scientific Morality? - (The Moral Landscape by Sam Harris)
The argument here is that not only can you have a rationally based morality, that it can also be a much better morality than those derived from religion.
Even if you don't want to discuss this topic, if you are interested in the topic of morality I encourage you to read this book. He also has some presentations on youtube that covers essentially the main points of the book.
If we long for our planet to be important, there is something we can do about it. We make our world significant by the courage of our questions and by the depth of our answers. --Carl Sagan