'Ender's Game' (as already mentioned)
Foster's 'Spellsinger' (we have the special effects to do it now!)
Dickson's 'Tactics of Mistake' or anything Dorsai. (technology would have to be updated)
Le Guin's 'Wizard of Earthsea' quartet (without the dreadful 'Tombs of Atuan') and 'The Left Hand of Darkness' (would be stunning)
The McCaffery 'Pern' novels. (instead they made that POS 'Reign of Fire')
I saw a made for TV movie of the novella 'Alien Mine' and they did a terrific job of it. With the effects they have now, a movie of 'The Sandkings', one of the best and scariest SF stories ever written IMHO would go down a treat.
Curval I'm shocked at your David Eddings selection! Talk about the epitome of the Tolkien ripoff industry!

Ravs