We went to see Avatar last night, and saw it in 3D at Cresta (since they have a newly upgraded theatre).
I thought the special effects and 3D were absolutely outstanding; totally seamless, and it felt entirely believable. I simply couldn't tell where reality became special effects. The 3D animations, textures, etc. of creatures, aircraft, space ships, and the environment seemed to me to be flawless.
The sound effects were impressive, very impressive indeed. Our theatre's speakers were really good; when ships were landing, or vehicles moving, I could feel the vibration right through my body; it felt really convincing.
The scenery was fabulous; much was filmed in New Zealand (what a surprise), but it was hard to tell what was real and what wasn't. The night-time ultraviolet was done beautifully, and I loved that; the night-time animal and plant life was lovely.
However, I thought the story was rather predictable and dull - essentially, Dances with Wolves on an alien planet, which was rather a pity given the interesting concept of the avatar. The characters were rather distant, and I found it hard to empathise with them in any way; sadly, they also seemed to largely be stereotyped caricatures, where you could predict exactly which role each would play. Acting was good, within the limited ambit of the characters, though I did think Zoe Saldana was especially good.
James Horner's score was a veritable pastiche of copy & paste from his other scores - Titanic, Enemy at the Gates, Star Trek, and others. Very derivative, and not particularly interesting.
( More, but with spoilers )
The film could have been so much better, but between hiring Weta and ILM, I guess there wasn't enough money left over for an innovative script.
Edit for score.