So, a couple of weeks ago I wrote down some thoughts about the Game of Thrones TV show. Today, after having read the book and seen the show, I can make comparisons.
Book: Three main factions in one country fight for the crown. In the north, guards notice mysterious forces beyond the wall. In the south, a kingdom fights to retain the throne. In the west, an exiled princess struggles to find her place in the world.
Movie: The movie plot is essentially the same. This is a very good reproduction of the story!
Most of the major plot points align. All of the main characters are there, and all of the same events happen.
There are still some differences between the two versions. The TV version is much more sex oriented. You can hardly get an HBO show without that though. There are openly gay characters in the TV show that are not in the book. Some of the characters are different. For example, Catelyn in the book is kind of whiny and annoying. In the show, she is awesome. The dream sequences are different and more interactive in the book than in the movie. Some of the internal thoughts have to be said in the show, which is to be expected. They also skip some of the lesser scenes in the show, such as much of the traveling scenes.
The book is long. Very long. So is the show, for that matter. However, if you only have time for one, I recommend the show. It is not different enough to make it worthwhile to read both in a time crunch. However, if you want to know the extended edition of the story, then you should read the book.