The Predicament of Belief by Philip Clayton and Steven Knapp: Without a doubt, this is my favorite book of 2011 (although I admit a strong personal bias since I am a graduate student of Clayton's). Clayton and Knapp make a strong argument for a type of panentheism in dialogue with the most current understandings of science and trends in philosophy. They then argue for 'Christian minimalism', showing how believers can maintain an authentic, humble, yet vibrant faith in line with much traditional thinking about the Trinity, creation, Jesus, the Spirit, and eschatology. Not quite orthodox, but not radically liberal either. The theological program set forth by the authors is entirely balanced, rational, and persuasive. I started blogging through the book here, here, and here.
Eaarth: Making a Life on a Tough New Planet by Bill McKibben: Ecology has been a big topic for me this year as I read widely in the growing field of eco-theology. Nobody explains the current situation of our endangered planet better than McKibben, a veteran environmental journalist and activist. This is his most recent book, a sober yet still optimistic call to radical changes in the way we live and organize society in an ecological age.
Process Theology: A Guide for the Perplexed by Bruce Epperly: I wrote a review of this book on the blog that you can read here. This is my new favorite introductory text to process theology.
The Church is Flat by Tony Jones: I also wrote a review of this book that you can read here. One of, if not the best introduction to the emergent church movement.