I feel these movies do stand alone and you do not need to read the books. It does help for the sake of comparison or supplemental information, but there is absolutely no need to read them to know what's going on.

I agree with you that a movie should be able to stand alone without supplemental multimedia to aid in the understanding of it. Maybe that's why I hate Mulholland Drive so much. It made absolutely no sense and everyone I talked to about it said that there was some online source that helps you understand it. What kind of BS movie requires you to do outside reading to understand it? Load of crap. Fortunately, LOTR was not like that. I saw FOTR before reading anything and I followed it just fine.