I'd be remiss if I didn't suggest Pilgrim's Progress. I actually got 2nd place in r/Reformed's essay contest a few years ago for my essay on why everyone should read Pilgrim's Progress. His book Holy War (which is similar in concept, i.e. a poetic narrative detailing the life of a Christian) is just as good, but not talked about enough.
As far as doctrinal stuff goes, The Intercession of Christ: Christ, a Complete Savior is one of the best theology books I've ever read. Its essentially an exposition on Hebrews 7:25 and it is masterful. My one note of warning is his little section about how Jesus suffered torment in hell after he died. Other than that, I remember only good things about the book and would highly recommend it.