I picked up a Newsweek a few weeks ago that featured a discussion between Rick Warren and Sam Harris (April 9, 2007). This Wednesday night Nightline will feature a debate between Ray Comfort & Kirk Camron (yes, from Growing Pains), who use the Ten Commandments as a way to help people confront thier own sinfulness, against a group called the "Rational Response Squad" who encourage people to take the "blasphemy challenge" and record their own personal statement rejecting God and post it on YouTube.
This Athiest v. Christian debate is getting a lot of play. Although I don't believe that every believer has to take a graduate-level course in apologetics, we do need to know how to "give an answer for our hope" The further we move from a shared set of values as a society, the more confrontation there is going to be on this subject. I believe one of the best defenses of the Gospel will be how we live. Jesus said, "Let your light so shine before men, that they may see your good works and glorify your Father in heaven."