In this video, Dr. William Lane Craig debates R.I.G. Hughes on the subject: Agnosticism vs Christianity. This took place at University of South Carolina, sponsored by Campus Crusade for Christ. From YouTube: "Hughes argues for the agnostics' position by explaining that neither logic nor science has anything to say about the existence of God. Any arguments for God come from an extra-logical premise. Craig reveals, however, that the claim "we cannot know that God exists" is a huge claim that needs to bear the burden of proof. He goes on to show that there are different forms of agnosticism and that rational agnosticism is compatible with Christian faith. Dr. Craig defends theism while presenting a multi-faceted argument for the untenability of agnosticism." Video part 1 here; part 2 here. Enjoy this old one.

"To say that we cannot know anything about God is to say something about God; it is to say that if there is a God, he is unknowable. But in that case, he is not entirely unknowable, for the agnostic certainly thinks that we can know one thing about him: That nothing else can be known about him. In the end, agnosticism is an illogical position to hold to."

— J. Budziszewski
Quoted in Ron Rhodes, Answering the Objections of Atheists, Agnostics & Skeptics, p. 25. 

"An agnostic position is one that leaves open the question whether there exists a god or gods, professing to find such a question unanswered or unanswerable. For the atheist, the question has been answered, and in the negative."

- Jaroslav Pelikan

Jaroslav Pelikan (b. 1923), U.S. theologian. "Atheist/Agnostic," The Melody of Theology: A Philosophical Dictionary, Harvard University Press (1988). Citation.