The sword of Shannara was made into a game. More of a narrative game, little action, but I played it through after reading the book. Wasn\'t awful, but only if you enjoy the narrative-story genre.
Lord of the flies is a book which I can\'t see staying true to the story and being successful, and it isn\'t a premise that can be expanded to other locations than a small group on an island.
Most of the others I can see being made into games, although I would stay away from the HALO book, just because they may as well write a new chapter on the storyline if they make a new game.