Grymar said:
My favorite wouldn't work...The Chronicles of Thomas Covenant. He's too much an antihero to make for a good popular movie.
Maybe the Riftwar saga by Raymond Feist?
Riftwar would be cool.....but is it well-known enough?
I'd love to see Memory, Sorrow, and Thorn by Tad Williams, but I doubt it would happen. Or Otherland...
Neither of those two series might be well-known enough either though.
I think Raymond Feist's "Faerie Tale" could make a great movie...horror/fantasy about the Faerie Folk...
What about Terry Brooks' Shannara series? Weren't they good sellers?
GRR Martin's Song of Ice and Fire...but I guess HBO has that one locked up for now.
There are likely tonnes of good movies that could be done about historical periods too. I'd love to see a well-done military epic about Napoleon....but they'd have to make him an American in the movie, and that, obviously, wouldn't work

Alternatively, movies about Hannibal (wasn't Vin Diesel going to star in one?), or what about something about Charlemagne? A movie about Ivanhoe?
What about Sigfried?
Banshee