http://en.wikipedia.org/wiki/Cornelius_Van_Tilhe's a strange case for me. his great influence is on conservative Reformed/neo-Calvinist types that I find to be anathema, but he himself was quite entertaining as a speaker, extremely familiar with the depths of many great thinkers, was able to understand and have dialog with Barth.
I will confess to not having tried to read any of his major stuff, nor his full-length defenses of 'presuppositional apologetics', the buzzphrase that he's most associated with.