So far my favorite read has got to be Mere Christianity by C.S. Lewis. This is, hands down, the best book I've read in a long time - perhaps ever. Lewis has a way of making abstract things easily understood. Absolutely LOVE this book. I'm hoping for my own copy for Christmas! (Update: I did get Mere Christianity as part of a C.S. Lewis anthology. Also loved The Great Divorce.)
Another one I read and really enjoyed was Red Letter Revolution by Shane Claiborne and Tony Campolo. I did a review of it in one of my blog posts. Definite must read as far as I'm concerned.
Having never read anything by Philip Yancey, I am so happy I picked up Vanishing Grace. This was a book that I read slowly, allowing different things to "marinate" for a while before going on to read more. This is another must read for anyone who wants to live out an authentic faith.
This one is somewhat of a surprise entry for me. I thought I would like Brant Hansen's book, Unoffendable, but I had no idea how much I would like it. It's not a popular idea, that of giving up the right to be angry or offendable, but Hansen's style is so easy going, yet thought provoking, I thought I would give it a try. This is one of those books that I recommend to everyone I talk with, but I'm not willing to give up my copy of it!