There was a computer game I would love to see made into a film, albeit with real actors - not CGI. It was called Hell: A Cyberpunk Thriller - fucking awesome story, mad twist at the end, one of the best games I have ever played storywise, fucking cool atmosphere as well - although most cyberpunk has that. It actually had Dennis Hopper and a few other well known actors in the game.
Someone mentioned some Christopher Pike books - just about anything he has wrote would make a great movie - I would personally like to see Scavenger Hunt (cool, twisted shit

), Road to nowhere (absolutely love that story and I think it would make a great movie), and the starlight crystal (very wigged out).
Of course there is still a lot of Stephen King books I think would make great movies, and ones that have been made into movies that should be done better. The Dark Tower series should be made into a big budget TV series.
Also the Mars series by Kim Stanley Robinson would make about 6 good movies. Although doing it properly would be a task comparable to actually colonising mars.
1984 by Orwell and Fahrenheit 451 by Ray Bradbury would make amazing films if done right.
Spellsinger series by Alan Dean Foster would also be a good choice for a transfer to the big screen - quirky characters, witty dialogue.