Obviously anyone's recommendations are going to tell you as much about that person's philosophical preferences as about the actual books. We might be able to do better if you told us more about your own interests and prejudices. Anyway, here are a few recommendations:
Ethics and (technical questions about) personal identity: "Reasons and persons", by Derek Parfit. Quite heavy going, but Parfit's an outstandingly clear thinker and there are some very good ideas here.
Applied ethics: "Living high and letting die", by Peter Unger. Argues for the counterintuitive conclusion that basically all of us in the affluent West have an obligation to do (not just somewhat more but) vastly more for the least well-off.
Philosophy of religion (from a definitely atheist perspective): "The miracle of theism", by John Mackie. Quite dense, but well written, clear and mostly fair. Much much more seriously intellectually than any of the recent "New Atheist" books.
Philosophy of mind, epistemology, ethics, decision theory, philosophy of physics, many other things: "Good and Real", by Gary Drescher. "A breathtakingly original assault on all the Big Issues!", says Daniel Dennett, and he's right.
Recommended on just about any topic: the "Oxford Readings in Philosophy" series of anthologies. Each volume consists of a lengthy introduction followed by somewhere on the order of 10 important articles from the primary literature. Generally very approachable and well selected.
Ethics and (technical questions about) personal identity: "Reasons and persons", by Derek Parfit. Quite heavy going, but Parfit's an outstandingly clear thinker and there are some very good ideas here.
Applied ethics: "Living high and letting die", by Peter Unger. Argues for the counterintuitive conclusion that basically all of us in the affluent West have an obligation to do (not just somewhat more but) vastly more for the least well-off.
Philosophy of religion (from a definitely atheist perspective): "The miracle of theism", by John Mackie. Quite dense, but well written, clear and mostly fair. Much much more seriously intellectually than any of the recent "New Atheist" books.
Philosophy of mind, epistemology, ethics, decision theory, philosophy of physics, many other things: "Good and Real", by Gary Drescher. "A breathtakingly original assault on all the Big Issues!", says Daniel Dennett, and he's right.
Recommended on just about any topic: the "Oxford Readings in Philosophy" series of anthologies. Each volume consists of a lengthy introduction followed by somewhere on the order of 10 important articles from the primary literature. Generally very approachable and well selected.