Some ideas to consider: are the best adaptations ones that are faithful to the book or ones that differ in some way? Is the film's greatness dependent solely on the novel, or is it great only because of the visual effects?
I'd say the majority of the Michael Crichton books have led to decent to great film adaptations. The best one that owes it to graphics is probably Jurassic Park. The best adaptation, either Sphere or Andromeda Strain.
You can help the HubPages community highlight top quality content by ranking this answer up or down.