1. Mystery of Capitol by De Soto fundamental changed how I view the world.
2. Book of Job changed how I viewed tough times in life 
3. Knowing God by J I Packer also changed my who life from the ground up
4. Lord of the Rings Trilogy changed my taste in story telling when I was young. 
5. Mere Christianity by c s Lewis had a huge impact on myself at the time I read it.

 first 5 that came to mind!