I have seen Avatar twice at the cinema, both times in 3D. The first time I found the 3D distracting, probably because I am not used to it. True, the three-dimensional effect is not ‘in-your-face;’ it is used to enhance the movie and create greater immersion, a feeling of ‘being there;’ however there are a few scenes with soldiers milling about and I had to keep checking that this was part of the film and not people walking around the cinema itself! Yes, the 3D is that good! It makes you believe you can reach out and touch things (the illusion only ruined when you try)!
The CGI is groundbreaking in itself; the alien race, the Na’vi, are so convincing, so realistic, the only way to tell them apart from real people is… they’re blue. Likewise the terrain, plants and animals that make up the planet of Pandora are breathtakingly realistic. You could not do better if you dropped a man off on an alien world with a video-camera.