4. The Silmarillion (mini-series)
Even though the Hobbit was a bit of a disappointment, an adaption of the Silmarillion would be a good thing. The Silmarillion would probably work better as a Game of Thrones style mini-series rather than a series of films as the Silmarillion is a collection of different stories rather than a single, consistent narrative. The earliest parts of the book such as the creation of the universe could be omitted and the series should probably start sometime around Morgoth's theft of the Silmarils and the ensuing voyage of the Elves to reclaim them. The Silmarillion's size and scale hasn't really been done at the TV level before but with the success of the Lord of the Rings trilogy and the Hobbit financially, the Silmarillion should be able to get enough funding to do the novel justice.