I have not read many books that also have movies, guess I have been lucky. However, I still think that I prefer the visual medium that the movie would offer over the book.
I'm with Hwo on Harry Potter, I prefer the books but I do enjoy the movies too; however, I read the books first.
With LOTR I'll be doing it the other way round. But my boy will have the books read to him before he sees the movies, so it'll be an interesting experiment.
I've got three kids who are all big Harry Potter fans. I've read them all myself, and have individually read them to each of my kids. I'm currently a few chapters away from finishing the 7th and final book to my youngest. It's a little emotional knowing it will probably be the last time.
Yeah, each to their own. When I was in my teens and early 20s I never really thought about kids; I might well have ended up not bothering but in the end I got my then girlfriend knocked up and the choice was taken away from me.