Patristic popularizer Aquilina has posted his Top 20 books about early Christianity.. Worth a look.
My two cents: The Quasten Patrology series is excellent. I bought it years ago, and it's an excellent reference source for all things Patristic. I found the Pelikan book hard to read, for a modern book. Newman's book on Development is also kind of difficult, but not as far as nineteenth-century non-fiction writers go.
With respect to Newman's book, I'm humorously reminded that Orestes Brownson thought he was a heretic for writing it. Newman and Brownson were about as opposite, personality-wise, as possible. They were both English-speaking, Caucasian, converts, but the similarities abruptly end there.
