The Power of Now - Eckhart Tolle
The Four Agreements - Don Miguel Ruiz
In my humble opinion, these two books alone, have the ability to change one's life.
The painbody visualization was especially therapeutic to me and helped me to cope in better ways than I would have otherwise.
But on the other hand I find most of his philosophy just bonkers.
The book is bit like "drawing on the right side of the brain" - great exercises wrapped in non value adding chaff.
I'll also mention Vagabonding by Rolf Potts -- a great book that's as much about travel as about life.