Actually, I have to edit myself again, as there are actually several stories in the Dark Tower series, plus other stories that are related in some way. I had to think for a minute.

The Dark Tower Series

The Gunslinger
The Drawing Of The Three
The Waste Lands
Wizard And Glass
Wolves Of The Calla
Song Of Susannah
The Dark Tower

Other books with related events, characters, places, etc.

'Salem's Lot
From A Buick 8
Black House
Hearts In Atlantis
The Stand
Insomnia
Rose Madder
Desperation
The Regulators
Bag Of Bones
and at least one story in Everything's Eventual

Dances With Wolves is definitely one of my all-time faves...but I was very surprised to see how thin the book was...

I think it is very rare indeed to have a movie as good as the book. I much prefer the books. I love to use my own imagination instead of Hollywoods.

A lot of times the books are better but in all due respect some movies have done the books they were based on justice. Example:
Dune
Long winded a little and sort of like a space age Lawrence of Arabia meets the Count of Monte Christo with a dose of Braveheart but the book was a decent story.
The first movie:
SUCKED SEEDS FROM CUCUMBERS! It missed a lot of important details and deviated from the book hard.
Then Sci Fi Channel did their version of it:
Much MUCH better. it did the story justice and they tried real hard to keep it true to the book.
Now keep in mind that it is hard to get all of a given book into a movie of 1 1/2 hours.
Animated Movies:
Akira:
The comic book was spectacular with incredible artwork and a very deep story line about government tampering with psychic forces that cause Tokyo to be destroyed by what looked like an atomic blast. Years later Tokyo is rebuilt and the government is up to its old tricks. The story revolves around a biker gang and a military commander in charge of a covert project and some of their test subjects. The government uses an experimental drug and unlock the powers one of the teenage bikers had and his power not only manifests itself uncontrollably but he begins to consume everything around himself.
The Comic book was Two Thumbs up and a bag of Ruffles WITH Hagen Daas! It was that good.
The Movie:
A few details were missed. Overall though it was the story and not much was left to be explained. The artwork was spectacular! I own it on DVD. Nuff Said!
Mists of Avalon:
The book was DEEP! It got into the deepest details of druidic life and the worship of the Earth Mother with a lot of legend mixed in. The book was excellent reading. You will never look at King Aurthur the same.
The Movie:
Again it would have been impossible to get all of the details of the book into the length of the movie. The movie did however manage to do a good job telling the story. The visuals were great, the acting was on the mark, and it did explain what it had to. I will eventually own a copy of this movie as well.
For the Classics:
I Robot:
The Issac Azimov story was ahead of its time. It is classic Sci Fi. It was a touch on the dry side but it did touch on the issue of What if we did make an intelligent thinking machine?
The Movie with Will Smith:
Not bad. Great visuals but not at all what the original story was about. It only used the Azimov story as a loose foundation for their story.
2001 A Space Odessy:
The book was OK but it was VERY dry. This is one case where the movie was better than the book.
Jaws:
The book was fine but again it is not as scary as watching the movie.

Then again it is all Apples and Oranges anyway...

That is a rare exception, they took a short so/so book & made an excellent movie. One of my favorites.