One of my all time favorites is a book that was popular in the 60's. It is a thin book with a powerful message. The Seven Steps to Higher Conscienceness. I also use my AA book and spiritual readings and meditations. One of my favorite morning mantra's is "All of us living love"

I have a couple of favorites - Velvet Elvis by Rob Bell (teaching pastor at Mars Hill Bible Church), and Blue Like Jazz by Donald Miller. Both offer insight to following Christ versus just going to church. Christians and non-Christians can gain valuable knowledge of why we "do what we do", and both books dispel some of the hypocrisy that we feel about "religious people".

One of my favorite books on spiritual living is a book by the name of 'The Normal Christian Life' by Watchman Nee. Watchman Nee was an educated Chinese lawyer before he found Jesus Christ as his personal savior. His book shows the difference between the 'average' and the 'normal' christian. It aids a believer is seeing the difference in a personal savior and going to church.
Watchman Nee was imprisoned for his faith in Jesus Christ and was martyed to death by the Chinese government for refusing to deny Christ. Maybe something in his book was worth knowing?...