I've already mentioned some of these sources in other posts...
But here I want to mention the absolutely inspiring spiritual teacher Wayne Dyer. He has written volumes of books on such topics including the Tao Te Ching, Change Your Thoughts Change Your Life and The Power of Intention.
I have particularly enjoyed his PBS specials as well as his audio teachings for his varied spiritual enlightenment and in finding "a calling." Speaking of the latter, his teachings have been especially instrumental as I sought my own life's quest years ago. I listened to his teachings for hours and days and even for years I've been playing them as the need arises to reinvent and re-associate the meanings of being (why we are here on this earth and purposeful existence) as he so eloquently describes as The Shift from the morning to the afternoon of our lives.
His lectures are deeply philosophical and enlightening for those that want to evaluate and deem their lives needing more. For those that are willing to take the time to seek God and/or a higher power to find what is missing in life. His lectures get you to think about life from a higher awareness and a higher consciousness... not as you knew it, but allowing yourself to be on this wavelength of inner peace to find out and discover more within yourself.
I have truly been inspired by his teachings as my own writings have touched upon this general need and desire to help individuals become more in tune with their greater self. You as the reader or listener of either of our works shouldn't assume there is or will be a blatant and outright answer to your problems and/or a solution to your living the life you want to live. His writings, just as in my own will get you to think deeper. To comb the depths of your soul into realizing more that you want out of life, and to realizing that your thinking and behaviors have hindered yourself from getting there.