Greg Koukl is one of my favorite Christian apologists. The guy is brilliant, articulate, and Reformed (which sets him apart in my book).
His material has been such an encouragement to me lately. If you are looking for a shot in the arm to bolster your faith, give his resources a try.
This particular lecture below is fantastic.
Also, he is perhaps best known for his book entitled Tactics: A Game Plan For Discussing Your Christian Convictions.
Lastly, Greg has a fantastic video (and book) dismantling moral relativism. You can find that video here.