I finally went to the cinema and saw Avatar in 3D. In brief, it gave me more or less what I expected, a good and entertaining movie, although I don't believe it will transcend to the annals of the sci-fi history because of several reasons.
First issue is the screening technology, even though this is actually the first time I experience it with Dolby 3D digital cinema. It makes sense offering another dimension to the audiences (and keep the interest and reasons to fill cinema chairs), but I am afraid that this is not the best movie to introduce this new technology because it has several fully colored sequences which are really fast paced with many camera turns and changes that can result in effects like getting sick and overwhelmed at the same time.
About the sound design, I can't say a lot because I was most of the time distracted by the visuals but some animal growls sounded to me very, very similar to early Jurassic Park dinosaurs :)
The story: bad guys against good guys. I do not want to offer spoilers, but I think the epic background fits well with the fiction and the emotive moments. Again, the visuals take the major responsibility on supporting the story, so the art work speaks for itself in some way.
Let's see what happens with the videogame.