I'll just start by saying, "What a mind-blowing movie!" James Cameron, who also directed the first two Terminator movies, Aliens, The Abyss, True Lies, and Titanic has managed to, again, deliver eye-popping visuals in Avatar. But these go far beyond what he has done in his previous films. For this movie he waited 14 years, since Titanic, for technology to advance far enough to create what he saw in his mind. What he saw were floating mountains, raw, untouched wilderness, skyscraper-high trees, and the camera looking down from dizzying heights, and in 3-D, too. He used the 3-D to envelope the audience in the story, not to shock or scare them. He also used special effects in place of make-up on the actors who played the aliens in the movie. The technology used allowed Cameron to precisely map the body movements and facial expressions of each actor, so that each character seems far more real and natural than a character created by a computer-generated image would have previously.
But, special effects isn't all there is to the movie. Not by a long shot. The story concerns a paraplegic former marine who represents a corporation that wants to exploit the planet Pandora for its mineral resources. But the indigenous population, called the Na'Vi stands in its way and the company won't let it. The marine, named Jake, has his mind joined to an avatar, a being made the form of a Na'vi, so that he may gather intelligence on them in preparation for an attack on the Na'Vi village. But, as he spends more time with the Na'Vi, in the body of a Na'Vi, and falling in love with a female Na'Vi assigned by her tribe to teach him their way, which gradually adopts, he begins to question his orders and starts to see himself as part of the Na'Vi people.
The heart of the movie is not the special effects, but the love story, and the subtle theme of relationship with the environment.
Word is this maybe the first of a trilogy. I await the next with baited breath.