I'll begin with Wuthering Heights. I loathed the book, loved the film with Olivier.
Next, Blade Runner. Philip Dick' s novel (Do Androids Dream of Electric Sheep?) is scarcely coherent. Ridley Scott's movie is great.

Debbie Does Dallas

Hi,
 
TL;DR
 
(You know it's coming!  )

Into the Wild by John Krakauer. The Girl with the Dragon Tattoo trilogy. The movies were cool but the books were awesome!
 
Rocky
 
Edit: Oops I did this back asswards

bluzdog
Into the Wild by John Krakauer. The Girl with the Dragon Tattoo trilogy. The movies were cool but the books were awesome!
 
Rocky
 
Edit: Oops I did this back asswards

I almost did as well.  Maybe you should start the opposite side thread so I can post things like Dune, Hitchhikers Guide to the Galaxy and dozens more. 

There are many movie adaptions I love, but I can't think of any that beat the original book.

IMO it often depends on whether you've read the book before seeing the movie or vice versa.
For example the typical routine of cutting down the number of characters for the film, or compiling one film character using material of several characters from the book, can be very disturbing both ways. 

2001 A Space Odyssey comes pretty close.

2001 A Space Odyssey comes pretty close.
 
+1
 
 

I like 2001 Space Odyssey but I have to say, the book explained the ending a lot better than the movie....