G.K Chesterton has caught my reading and intellectual attention. I am working through Orthodoxy every Sunday(and only Sunday! this is Sunday #2) and have been impressed enough to procure several more books of his for my Kindle.
His writing thus far has been mentally challenging and spiritually charged; I recommend him to serious readers only, but to those that are serious, I recommend without reservation.
See his books and learn more about the man here. As I said before I am currently reading Orthodoxy but I have several of his books in the "Queue".