I finished reading the book recently and one of my first thoughts was "the movie is gonna stink". The book could very well be a Poe story the way it's written. Every word is chosen for the final effect. All the character's development and what he does is preparation for that crucial moment in the story, pretty much like "The Facts in the Case of M. Valdemar". You could even remove the ending and it would still be an awesome story.
And then when I thought about the movie the first thing that came to mind was all the possibilities for visual effects in the battle room. And now the first thing I see from the director is mentions of the battle room. So, are two hours of visual effects enough to build up the climax of the story? Will they split the novel in two to be able to do it in the second film? I sincerely hope they manage to get it right.
If you think the first book is a masterpiece, don't read anymore in the series. It will ruin it for you. :) I "like" some of the later ones, but none are as well-written, impeccably paced, or engaging as the first in my opinion.
I don't doubt we'll see some adaptation of the story for film, but at its core, I think it should hold up fairly well. Let's just hope we don't end up with Bean being a Jar Jar Binks character or something stupid like that.
FWIW Speaker For The Dead also won both the Hugo & Nebula awards. It's fairly different from Ender's Game, so I can see why some folks might not like it but I thought it was pretty good. It's worth checking out at least.
The series does tend to follow the law of diminishing returns. Speaker For The Dead feels more mature and literary, but was less fun to read. Xenocide and Children of the Mind, in turn, are scarcely worth getting through, and the payoff at the end isn't worth the suspension of disbelief or, indeed, the trouble.
IMO, Speaker For The Dead is the true masterpiece and Ender's Game is simply a necessary bit of back-history to setup events for the Speaker story to be told.
I've found that seems to happen with most novel series. I guess they suffer just as movie sequels do. From my experience, on average, quality is maintained for the first two books, and then it starts to nosedive.
I'd say read the whole Bean series, but only read the lastest in the Ender series. You'll get caught up with Ender and you don't have to wade through most of what many people have described as bad storytelling (friends).
And then when I thought about the movie the first thing that came to mind was all the possibilities for visual effects in the battle room. And now the first thing I see from the director is mentions of the battle room. So, are two hours of visual effects enough to build up the climax of the story? Will they split the novel in two to be able to do it in the second film? I sincerely hope they manage to get it right.