Neither of the films are really viable as adaptations - in fact the National Lampoon parody probably gives you more insight into the original novel than the films. The first one especially, the David Lynch one, is beautiful to look at but, well, it's a David Lynch film... The mini-series? Well they turn Princess Irulan (a minor character in the book) into a kind of decadent, late Roman Nancy Drew!

The things is, the book is so focused on the inner lives of the protagonists that it really does make for lousy film-making...