I don't know about life altering, but reading Dickens often helps me take stock and realize that I've got it pretty darned good... not only for what I have (roof, food, family) but also because of the basic freedoms I have here in my country.
*shrug*
Edit... the fact that Dickens is a smarty pants helps as well.
Try Discord's Apple by Carrie Vaughn. I really enjoyed it and while I can't really say it changed my life, I can say that it gave me a profoud respect for how good we have it in the American of here and now as opposed to the America that "exhists" in this book. While it did have a "religious" aspect is was of the Ancient Greek and artifact type. I found it to be a very good read. Im not sure what catagory it's in but you can check it out on Amazon as far as reviews go to see if it's your cup of tea.