Peter Jackson's The Lord of the Rings trilogy are all in the top twenty of the world's most successful films. The Hobbit has also now been made into a trilogy by the same team which, despite mixed reviews, is unlikely to be anything other than a huge financial success again. It's clear, therefore, that not only is Peter Jackson a great film maker, but he's working with some of the best literary material available: J.R.R. Tolkien is a wonderful story teller. So, having exhausted four novels of Tolkien's almost in-exhaustive bibliography (material of his is still being published for the first time), what should be made next?
Our first suggestion is Letters From Father Christmas. A very far cry from Middle Earth, this suggestion is probably induced by the festive season, but a television series adaptation would be an amazing addition to Christmas viewing. Tolkien wrote letters to his children, posing as father Christmas, throughout their childhood and in 1976, when they were all grown up, a book of them was published. They are all truly beautiful, hand illustrated stories about Father Christmas and the misadventures of the Northern Polar Bear. They are a really wonderful read and it would be great to watch as well.
The other, more obvious appeal to be made is for The Silmarillion. It's one book with five inner books, that delves deeper and deeper into Earth's past, full of smaller stories and fables from the fictional universe of LOTR/The Hobbit which Tolkien created. The second book in particular 'Quenta Silmarillion' is all about Elves, Men, Jewels, and darkness and light. It's brilliant.
Finally, Tolkien wrote absolutely loads of sprawling narrative poems, many of which would be ideal for adaptation. In 2009, The Legend of Sigur and Gudrun was finally published for the first time, it's inspired by Norse mythology, and all about vikings and Gods, which is infinitely fun. It should be made into a film.
To be honest, anything from Tolkien would seriously great, so consider this a request Jackson- bring these to screen.