A great quote from the second one as he contrasted Christ centered preaching with two other forms: (a) preaching to the will (Christian duty and obedience) and (b) preaching for increased knowledge (Christian doctrine):
"If what we are doing [in preaching] is not creating greater intimacy and obligation to the Savior out of love for Him, then no matter what science [of preaching] we have pursued, we have not got the goal accomplished that God intended from his Word."
Along these same lines, iTunes U has an entire seminar by Edmund Clowney and Tim Keller on this kind of preaching (free--along with other Westminster Seminary lectures. Likewise, Gordon-Conwell has a half-dozen messages too (for a well-worth-it price).