Conversations with God by Neale Donald Walsch, either book 1 or book 3. Why? I'll copy from my blog:

I’m really good at seeing all of the subtle flaws and shortcomings of people, like in their writings, on the conceptual level, on the level of actual motivations and intentions, on the level of grammar and whether they choose the best possible word for the job, etc.. and the parts in Neale’s books where God speaks, it’s absolutely flawless. In all of those senses. That’s more an unusual occurrence as far as I’m concerned than you might realize. I’ve literally never encountered any text or spoken word so flawless in my life. So it makes sense that the explanation for that fact would be that it's actually God talking as is the premise of the books.

I mean obviously someone who’s trying to channel God is going to sound as perfect as possible, but this is a matter of subtle things, unconscious motivation, cognitive perfection and talent and grace at using language that you can’t do just by wanting to. and people want to sound perfect all the time after all.

Furthermore, the ‘energy’ behind the text, as in the messages it contains and the style, or maybe simply something spiritually tacked onto the text directly, was absolutely, 100% pure in my perception. It was so pure and neutral that it was almost unworldly. (I don’t know if I should say it was 100% neutral, because it wasn’t exactly indifferent, or he wouldn’t have had a reason to say anything, and I think he had some amount of passion about certain subjects, but it was neutral of biases or all but the most sublime energies or whatever.)

As for the information given in the books, it's very interesting and illuminating and pertains to so many issues at the core of life. And he said a few things that I'd always believed but had never heard anybody else say. I once even dropped a tear onto the page as I was reading, and it's not easy to make me cry.