When I was a freshman in college, Schaeffer was a major help, particularly his book Escape From Reason. He enabled me to move beyond a pietistic fundamentalism to a more thoughtful world and life view. Schaeffer and InterVarsity Press were constant companions. Schaeffer himself has escaped from fundamentalism but was, in my view, recaptured by it in his later ministry as cultural and political lines crossed.
Justin Taylor has linked Schaeffer lectures online from the Wheaton archives.