I read the book and seen the movie in every case listed.
Field of Dreams captured the spirit of the book Shoeless Joe. Wholesale changes to the plot were made, events rearranged, and a major character dropped. It didn’t matter.
Shindler’s List actually improves opon the very good book of the same name on which it is based. The power of the music, stark photography, and the outstanding performances brought the somewhat dry semi-biography to life.
Matilda perfectly captures the flavor of the Roald Dahl book of the same name. Children’s books seldom get the treatment they deserve when adapted; witness the truly dreadful Harriet the Spy movie taken from the wonderful book.
The Silence of the Lambs: A sublimely beautiful adaptation.
The Shawshank Redemption is based on a Stephen King novella, and almost perfectly replicates the events and moods in the story. Morgan Freeman’s voiceover work is flawless.
The book Psycho has inspired Psycho, The Texas Chainsaw Massacre, and Buffalo Bill in The Silence of the Lambs. The triple crown.
I Am Legend was made into one good movie, The Last Man on Earth with Vincent Price. It was later remade as Omega Man, but not nearly as well. It was highly influential on (read: it was ripped off) Night of the Living Dead.
Who Goes There? was the source for both versions of The Thing of which the John Carpenter version is far better, and all three versions of Invasion of the Body Snatchers all of which are good.
Where the Heart Is is one of those quirky, small town stories that made for a good book and a very good movie.
Get Shorty and Out of Sight are by far the best adaptations of Elmore Leodard’s work. They actually lifted sections of the dialog directly from the book for Shorty, and adapted it well in Sight.