Just Thought I'd let you know that this now released on DVD and I just watched it. There don't seem to be many comments of the film here, thought there are several long threads on the book itself.
It's been a while since I read the book, but it looked like a faithful adaptation and is pitched just right. I'd agree that Eric Bana and Rachel McAdams were good choices in their respective roles. The picnic field, the house and other scenes are just as I had imagined them, which is often not the case in film adaptations.
My wife and daughter noticed that they changed the thing about the future Henry used to convince Dr. Hendrick, from his unborn child having Downs Syndrome, to him Winning some Medical Prize. Why they would feel the need to change that detail is beyond me. Otherwise, to me it seemed exactly as the book and I've already said as much as I can on the story in those other threads.