Zen and the art of motorcycle maintenance http://www.amazon.com/Zen-Art-Motorcycle-Maintenance-Inquiry...
How to win friends an Influence people http://www.amazon.com/How-Win-Friends-Influence-People/dp/14...
Plus recently "Made to Stick" has really changed how I think about ideas and sharing them with others. http://www.amazon.com/Made-Stick-Ideas-Survive-Others/dp/140...
Spiritual: Book of Mormon, Book of Isaiah, The 4 Gospels in the New Testament
Relationship: The 5 Love Languages, Men are from Mars Women from Venus
Physical: Spark, The Vitamin D Solution
The Republic, by Plato. It introduced me to a whole new way of thinking.
The Gita. I later came to know about the chariot allegory in the Kathopanishad (http://www.atmajyoti.org/up_katha_upanishad_17.asp), and thought that the writer's depiction of the charioteer as Krishna and the rider as Arjuna was just brilliant.
A mind blowing explanation of consciousness. The jury is still out with most critics considering this wrong -- but nevertheless, it's an amazingly detailed (and well supported) theory of where consciousness, gods, schizophrenia etc come from.
I read this after listening to the following lecture: http://arc-tv.com/inspiring-heroes-great-leaders%E2%80%94fre.... His strength of character allowed him to escape slavery and abolish the practice in the United States.
Atlas Shrugged by Ayn Rand: http://www.amazon.com/o/ASIN/0452011876/
Don't buy the mass-market paperback, the writing and margins are so small that it is a pain to read. Spend a little extra for the larger version I linked to.
It's been described as "the first piece of literature since the Book of Genesis that should be required reading for the entire human race." 
Cosmos - helped me fall in love with Physics, and the sciences.
Tao Teh Ching - If I could tell you how it influenced me, we'd both have the wrong impression.
Tao Teh Ching: http://www.amazon.com/o/ASIN/0877735425
Given it was written in 1932 it surprisingly exposes present-day concerns.
But I'd agree that BNW has more to teach us about today - lots of us are losing/have lost the ability to think much beyond our next pleasurable experience.
Everybody should read it, or at least watch the video on Youtube. It changed my life.
I happened to bump onto the video at first (and watched over and over again) and finally decided to grab the book. Reading the book really like having myself in the story.
Go grab the book. It is worth a life.
"A Supposedly Fun Thing I'll Never Do Again" by David Foster Wallace, pretty sure this book has changed how a generation writes. At least it convinced a generation they'll never be as good as DFW.
"Norwegian Wood" by Haruki Murakami, which I like to think of as a Japanese C.i.t.R.
G.E.B. - power through it, soldier!
"Making Certain it Goes On", by Richard Hugo. An instructional book on how to write poetry, or to basically do just about anything. I highly recommend it to all programmers.
In the Beginning was the Command Line: http://www.amazon.com/o/ASIN/0380815931
Recently each of Alain de Botton's books (Status Anxiety, Pleasures and Sorrows of Work and Essays on Love) had a valuable lesson to teach.
Alexander Pope's 'Essay on Criticism' (poem, not a book) was one the first poems that I gleaned something from, and that opened up a whole new library of potential reads.
Alain de Botton: http://en.wikipedia.org/wiki/Alain_de_Botton#Publications
Essay on Criticism: http://books.google.com/books?id=KFc7AAAAYAAJ&printsec=f...
Corny as it sounds,, that book changed my way of thinking and indeed my life when I was around 18yo.
Free version somewhere online - but I own a first run edition. Amazing book about what you can do if you really want to, and how strong the human mind can be.
The Craft of Research (Wayne C. Booth, Gregory G. Colomb, Joseph M. Williams)
On Writing Well (Zig Ziglar)
The Craft of Research: http://www.amazon.com/o/ASIN/0226065847/
Little Schemer: http://www.amazon.com/o/ASIN/0262560992/
When Nietzsche Wept: