Cujo
This is one of the better-done adaptations of a Stephen King book, only because the filmmakers didn't really have to plumb the emotional depths King does in his work for it to work. It is, quite simply, the story of a giant killer dog trapping a woman and her young son in their car in a front yard out in the country.
Unconcerned with the subplots, it can zero in on Donna (Wallace) and Tad and their plight. It's tense more than scary and will appeal to fans of good horror premises rather than just King completists.
Unlike the downbeat ending of later adaptation The Mist, it also has a much happier ending than the book.