Sometimes it works and sometimes it doesn't. I agree that in general the book is an ultimatlely deeper experiance, simply because you can pack so much more into a novel than a two hour movie.

The Lord of The Rings Trilogy was well made. Peter Jackson had a stellar cast, and a great eye for detail. The side benefit is that they got a lot of people reading LOTR books afterwards.

Harry Potter, also well done, since JK Rowling herself is heavily involved in each one. All of them have been directed, written and produced well. The "kids" (now young adults) are all talented actors and I could not think of anyone playing Harry Potter but Mr. Radcliffe, who I believe will have a very bright future as actor.

anything based on Stephen King has been rather disappointing. I never bother with any of the films made from his books, the books are far better. I cringe when I hear that JJ Abrams was trying to do a film of the Dark Tower epic... Don't do it.

Dune, despite having a great cast, and being based on a massive epic, was dismally produced and the subsequent sci fi series a couple of years ago was not much better.