I just took my family to see James Cameron's Avatar, and it is magnificent beyond superlatives.
As I told a friend, Avatar is so good you won't believe it. You'll BELIEVE IT, which is why you won't believe it. It is so well-done, it kicks you beyond the "wow that's an amazing special effect stage" to being unaware that you're watching a movie and being absorbed in the story.
The story works at many different levels -- sci fi speculation, historical allegory, contemporary political tale, and individual psychological/spiritual metaphor.
Go see it.