Plantinga is interesting, but really rather a Platonist. His god as the creator of all abstractions notion seems to require massive semantic manipulation to work. Not that he isn't brilliant. Certainly Plato was, as were Augustine, et al. Worth reading, but fraught with necessarily esoteric problems which seem best suited to obfuscating the problem against which atheism reacts, namely a lack of evidence for god or gods.
Trying to update my sig ...