Let me start off by saying that not all of these books were released in 2009. Three of them were indeed released this past year, the two others in 2008. In either case, I read all of these books in 2009 and recommend them to all.
Praying the Psalms with the Early Christians by Mike Aquilina and Christopher Bailey
This fine book has become the nightly devotional that my wife and I read before going to sleep. It includes the RSV translation of 34 Psalms, with short reflections from the early Church Fathers. The short reflections are freshly translated in more modernized language. Some of the Fathers that are included are Augustine, Ambrose, Cyril of Jerusalem, Athanasius, and Jerome. This is a great little devotional book.
Meditation and Contemplation: An Ignatian Guide to Praying with Scripture by Timothy M. Gallagher, OMV
This fairly thin book has been a real blessing to me. While I always enjoy reading the Holy Scriptures for Bible study and teaching class, I have often felt that my praying of Scripture has been rather poor. Sure, I pray every day with the Bible, but it hasn't always been as fruitful as it should. Fr. Gallagher's book focuses on Ignatius of Loyola's two basic methods of praying with the Bible: meditation and contemplation. The book does a great job at explaining the Ignatian method, along with dozens of real-life experiences by the typical lay reader. For those of you who haven't been introduced to the Ignatian way of praying Scripture, this book is a nice introduction.
The God of Jesus Christ: Meditations on the Triune God by Pope Benedict XVI. You didn't think I was going to have a list of my favorite books of the year without giving a nod to B16 did you? Well, this is one of the books that was released last year, but it was required for my Christology class last Spring. I am glad that it was. This book is a collection of edited papers by the then Cardinal Ratzinger focusing on each of the three persons of the Holy Trinity. It seeks to answer the question that Rahner asked years earlier about whether belief in the Trinity mattered to the average Christian. Cardinal Ratzinger believes that the proposition that "God is three and God is one" is essential and "if this proposition had nothing to say to us, it would not have been revealed (29)." Let me finish with one of his quotes concerning the Holy Spirit: "Unlike Father and Son, the name of the third Divine Person is not the expression of something specific. It designates that which is common in the Godhead. But this reveals the 'proper character' of the Third Person: he is that which is common, the unity of the Father and the Son, the unity in Person. The Father and the Son are one with each other by going out beyond themselves; it is in the third Person, in the fruitfulness of their act of giving, that they are One (109)."
Covenant and Communion: The Biblical Theology of Pope Benedict XVI by Scott W. Hahn
As this book points out, while there has been many books written over the past few years about a variety of issues surrounding Pope Benedict XVI, very few, if any, have concentrated on his Biblical theology. Which is somewhat surprising, since the one major book he has released, as Pope, Jesus of Nazareth, is precisely a biblical examination of the life of Christ. (And of course, part II is set to be released next year.) This book proves to be is a fine overview, and it is written in a style that encourages the reader to read Benedict/Ratzinger for themselves. There are plenty of footnotes to entertain and delight those who want to do further reading.
Honorable Mentions (some of these I am still working on)
Kinship by Covenant by Scott W. Hahn
Inhabiting the Cruciform God by Michael J. Gorman
Justification by N.T. Wright
Screwtape Letters by C.S. Lewis (a true classic that I read for the first time this year!)
So, what are yours?