For once I completely agree with jediknightthesnoozy on something. I would love to see 1984 brought to film (and hopefully with the ending not being made happy). Some modifications might have to be made, but hopefully nothing that would change the essence of the story.
Also, a properly done Narnia series would be great. The Disney ones got progressively worse. They butchered the last one, the book of which happened to be my favourite. And my second favourite, The Magician's Nephew, hasn't been made into a movie yet. I don't believe The Last Battle has either, and that's also a popular one.