Not Crunchy (NC) posted some more good discussion fodder. Instead of consuming her comments section, I thought I'd compose my verbose response here.
NC's post centers on the concept of "innate morality." The basic assertion is that many moral distinctions are shared across myriad religions. This points to an innate sense of right and wrong, which is sometimes (if I can put words in NC's mouth) expressed through a religious worldview.
This is not a unique perspective. C.S. Lewis, discusses a similar concept in Mere Christianity. To me this "innate morality" seems to indicate there is a sensible reason many moral questions are answered the same in various cultures and religions (i.e. murder = bad, robbery = bad): We are all created by the same maker, who has left His "fingerprints" within us.
From this observation, that many "taboos" are found in disparate cultures, NC asks some questions, and draws a couple of conclusions. I'd like to address them here. Starting with...
First, "why does one need a detailed philosophy to understand how to live a righteous life? "
One doesn't. But when one is trying to live based on truth it behooves one to seek the truth, philosophically. This in turn can lead one to a certain religion in which one can more efficiently or effectively seek truth. Religion, in one sense, is a framework for truth seeking. Obviously, there is more to following a religion than simply seeking truth (such as fellowship with others, support during hard times, etc.) but it provides a way to seek for what is true. Insofar as religion points to truth (instead of error) it is useful for those seeking how to live a righteous life.
In addition, religion helps us define what constitutes a righteous life. Outside of religion, there is really no foundation for deeming one act righteous and another evil. Righteousness is an absurd concept if moral decision making is not based on an objective foundation. No such foundation can exist in naturalism; righteousness is entirely a religious concept.
Next question: "What kind of God would allow only a tiny percentage of His creation to have everlasting life?"
The answer is a just and holy God who cannot abide imperfection because His nature is perfection. But I'd change the perspective a bit. From a Christian perspective, God doesn't "allow" only a tiny portion to have everlasting life: He freely offers salvation from our rebellion, and only a tiny portion accept it. The rest choose their own damnation. God respects our free will too much to force us into Heaven. In truth, it is we who do not avail ourselves of the opportunity, offered to all, to receive God's grace.
Finally, a comment or two. NC writes that, "Christianity is one religion with hundreds of flavors. Each flavor's members seem to think that they are living the true path of righteousness. Islam - same thing." What I read from this is that exclusivity claims are bad (NC ties this to the question above regarding God only saving a few people.) What I see, though, is that the existence of these differences in no way negates the idea that only one true religious view can exist. Either orthodox Christianity is true or it is not. Either Islam is true or it is not. Both cannot be true, and neither can be true if atheistic worldviews are true. Instead of seeing problems in exclusive beliefs, I think it is better to seek out which of the competing claims is true. Don't reject all exclusivity claims because "everyone thinks their ways are right and everyone else is wrong." Instead, find out why people claim exclusivity, and investigate whether their claims are reasonable. The problem isn't that I disagree with an atheist, a muslim and a hindu. Rather, the problem is that at most only one of us has a true worldview and the rest of us are in trouble.
Finally, the ending comment from NC reads as "[t]here is beauty in our differences, but also a dark side to choosing sides." I don't see a dark side to choosing sides. I see a dark side to choosing the wrong side. Everyone chooses sides. The question is, will you choose the right one? Worldview and religion decisions have the possibility of impacting eternity if we theists are right. Such questions need to be investigated seriously and honestly. Don't worry that people differ, worry instead that you are seeking the truth regardless of the different opinions that others have.