Let's begin with Dr. Tim Keller. Why? Because he is a rarety to my mind. He seems to see what the culture needs now, rather than being oblivious to the now while fighting culture from twenty years ago. Oh, and he is helping to reclaim the authentic Gospel... a very good thing. On a personal note, God has used Tim Keller to change fundamentally the way I look at Christianity, both personal and corporate. So yeah, I like him. Plus, he's pals with D.A. Carson, just icing on the cake. Here are the must listens:
Smashing False Idols- A three part series on Evangelism. He talks about how to impress sinfulness on modern folks, since many don't believe in the same set of norms as older generations. It'll kick your own pious butt, too, so don't say I didn't warn ya.
Prodigal Son series- Keller in a nutshell. You can get a better idea of what he's about here quicker than any other earcandy. And to those who have ears to hear, let them hear.