This may not be what you're after, but I have to go with the Haruhi Suzumiya light novel books, as well as the works of John Green. They don't inspire me in terms of giving huge grand-scale revelations for my life, but they are the books that I can pinpoint as making me go: I want to write fiction like this. And I'm guessing it's slowly working, because I've had people I've gone to for feedback say "Hey, Chris, you know you kind of write like John Green?"
Aside from those, I like books that give me a lot to think about. More of who you are comes from inside, than outside. So books that help you look at the world differently can help to make you who you are. For me, Battle Royale by Koushun Takami did that. 1984 by George Orwell did it as well.