Now, for Sam's list:
The Top Fifteen Books of the Last 50 Years
(that should have been most influential but sadly, in many cases, were not)
(1) Desiring God: Meditations of a Christian Hedonist (Multnomah Press), by John Piper. This is the most important and life-changing book I’ve read in the past thirty-five years. The gospel of Christian Hedonism warrants a global hearing.
(2) Knowing God (IVP) by J. I. Packer. I’ve heard Packer say no one is more surprised by the influence of this book than Packer himself. Virtually everyone I know has read it and testifies to its glorious portrait of the grandeur of God.
(3) Systematic Theology, by Wayne Grudem (Zondervan). Grudem’s theology is must reading. Not just for scholars, this wonderful book is being used in Sunday School classes, small groups, and bible studies of every sort.
(4) The Pleasures of God: Meditations on God's Delight in Being God (Multnomah Press), by John Piper. Runs a close second to Desiring God in the Piper corpus of writings.
(5) The Presence of the Future (Zondervan), by George Ladd. This excellent treatment of the kingdom of God marked the end of dispensationalism in my theology.
(6) Jesus and the Victory of God, by N. T. Wright (Fortress Press). I don’t agree with everything Wright writes, especially his doctrine of justification. But this is a marvelous and ground-breaking achievement in dealing with the ministry of Jesus, the kingdom of God, and the proper understanding of the relationship between Israel and the Church. Having said that, I should say again that you must read Wright with discerning eyes.
(7) The Holiness of God (Tyndale), by R. C. Sproul. This excellent book restored in many of us a reverence for the transcendent otherness of God and how it impacts our daily relationship with him.
(8) God’s Lesser Glory: The Diminished God of Open Theism (Crossway) by Bruce Ware. Would that all might read this superb refutation of Open Theism. Bruce has done a marvelous job of demonstrating both biblically and theologically the exhaustive divine foreknowledge of God.
(9) The Doctrine of God: A Theology of Lordship, by John Frame (Presbyterian & Reformed Publishers). Although this should exert mind-shaping influence on the Christian world, few are inclined to apply the necessary mental energy required to profit from this wonderful book.
(10) Surprised by the Power of the Spirit (Zondervan), by Jack Deere. Although not all will agree with this selection, I remain convinced that Deere’s careful and biblical refutation of cessationism is the best available on the subject. Highly recommended.
(11) Let the Nations be Glad! by John Piper (Baker Books). The best book on missions I’ve ever read.
(12) Recovering Biblical Manhood and Womanhood, edited by John Piper and Wayne Grudem (Crossway). This was one of the first, and certainly the most influential, of books explaining and defending biblical complementarianism.
(13) The Gospel According to Jesus (Zondervan), by John MacArthur. A ground-breaking defense of the Lordship of Christ and a thorough-going refutation of antinomianism.
(14) Civility: Manners, Morals, and the Etiquette of Democracy (Basic Books), and Integrity (Basic Books) by Stephen Carter. These are great books, especially Civility. In a day of selfish disregard for the rights and dignity of others, Carter brings both a rebuke and a refreshing word of instruction.
(15) Jonathan Edwards: A Life, by George Marsden (Yale University Press). I had to include something about Edwards!