William Lane Craig, a Christian apologist, argues that an objective morality can only make sense in the context of God, and that any naturalistic, materialistic, atheistic worldview is ultimately inconsistent with a morality universally binding on everyone. On the other side, Dr. Louise Antony argues that even if God existed, God could not possibly be the source of any morality worth having, and that if God were morally good, It would have to be good for secular, and not religious reasons. Both points are, of course, natural implications of Antony's beautiful articulation of the Euthyphro dilemma.
Whatever side of the issue you stand on, you are sure to be stimulated.
Of course, Craig's attempt to show the Euthyphro dilemma is a false dilemma only moves the problem one step back... to exactly the same problem, as this brilliant cartoon demonstrates:
You might also want to check out a debate between Richard Dawkins and Alister McGrath, or between Alister McGrath and Christopher Hitchens on similar topics.
Did anybody fall for the ontological/semantic distinction? Total distraction, but what a slick move!