Amazing visuals! A simplified and decently told story ( nothing much new or pathbreaking on that front tho)
Having laid bare our mother earth, the humans now want to mine the super valuable unobtainium ( yes i kid you not!) from another world - Pandora ( yes I still kid you not! ) Unfortunately for the humans, but fortunately for the storyteller, the bulk of the deposits lie right under a central settlement of the natives, a lovely people called the Navi, who're fully in touch with their mother pandora. So humans send in Navi looking, human controlled avatars in to persuade/spy. And I guess its not hard to guess the story from there.
However, I don't think would have the same appeal 20 years from now. There's really nothing beyond the scenic beauty and awesome cinematography, special effects, and the like. Nothing lasting really beneath the surface. And I can't help wondering , if such effort and money had to be spent, couldn't it have been on something lasting at least? But then perhaps it was a business trade off, a simpler , black and white story would have a more mass appeal.
Well so be it, for now its certainly worth a watch, specially in 3D. Luckily, the movie doesn't use its effects ( 3D, cgi, or anything else for that matter) simply as gimmicks. Within the parameters of story telling, it keeps props as instruments of the story telling, and not a proclamation of "I can so I will" .