Who is this me that is supposed to be changed? What is my identity? If the real me is consciousness and therefore eternal and unchanging... well no book has ever changed me.
But of what I can consider as some sort of self... hehehe...
Intellectually these books shattered my reality and opened my mind:
Alasdair MacIntyre - After Virtue
Friedrich Nietzsche - Genealogy of Morality
The Bhagavad-Gita and The Upanishads
Dare I say the writings of Steve Pavlina ???
I don't neccessarily agree with all the conclusions (how could I when they are so wildly contrasted!) but the lines of reasoning they take you down and the possibilities opened up are incredible.
edit : how could I forget the entire works of Plato in my list ??????!!!!!