Here's my list:
The Final Quest by Rick Joyner
Joyner claims to have experienced everything that happened in the book through a prayer vision. Whether true or made up, this book is full if insight that you won't find anywhere else. The man who recommended it to me even said he refused to read the last chapter because spiritually, he wasn't ready for that kind of responsibility.
Animal Farm by George Orwell
I see that somebody else has recommended 1984, which is a good book, but I found that Animal Farm had many parrallels to the church. Orwell, a.k.a. Eric Blair, had a very good insight to the nature of communist/socialist government and an almost spooky way of imagining the future, because much of what he wrote in 1984 is slowly coming to pass.
The Road Less Travelled by M. Scott Peck
Don't let the title fool you. This isn't a Christian book. The author uses strong, foul language sparodically and does cite recommendations that he's made to patients of an immoral nature. It's a self-help book/psychology book, but the author does inadvertently preach a gospel of love, personal responsibility, and growth that I have not heard anywhere else--even through purely Christian outlets.
Racing to Win by Joe Gibbs
Joe Gibbs was a football coach and now owns Joe Gibbs Racing, a NASCAR franchise that fields the #18 Chevy of Bobby Labonte and the #20 Chevy of Tony Stewart. This book is a memior of sorts, mixed with a Bible study, mixed with a business book. It's an easy read and is chocked full of wisdom.
The Power and the Glory by Graham Greene
Greene was, in my opinion, the greatest writer of the 20th centry. I know, that puts him in good company. This book is the story of a priest who isn't much of a man at all in a country where a military revolution has resulted in a bannana republic. Someone smarter than I could tell you exactly when this happened and the political parties involved; I can only tell you that this is a story of redemption, masterfully told in a slow, powerful style. Also check out Greene's other work, particularly
The End of the Affair, as it had an underlying message of finding God in a story about adultry and deciet.
As a bonus, I'd also ask you to check out my book someday, if it ever gets published.
Trust me, you'll hear about it here if it does.