No account should be taken of how complicated they would be to make or how costly etc etc.
Purely list them on their merits not how possible it would be to do.
Tom sharp - Riotus assembly.
A black comedy book (no pun intended) about the appartide South African Police. Had me in stitches all the way through it.
Tom Clancy - Red Storm Rising.
A 1980's book about a 3rd world war. (written before the fall of the Berlin wall). Would be a complete knightmare to film for a number of reasons but if done well i think it would be the war film to end all war films.
David Eddings - The Tamuli trilogy.
Good old fashioned sword and scorcery. I love all 6 Sparhawk books. They appeal to the fantasy adventurous little boy inside of me.
David Eddings - Belgareth the sorcerer.
As above good old fashioned S&S.
These are in no particular order though given a choice i'd put Red Storm Rising first on my list. There are loads of others that i will mull over and add as i think of them.