The story was very unoriginal, the characters were extremely cliched, everything that occurs can easily be predicted well ahead of time, the dialogue was often cringe-worthy; the score, the pacing, pretty much everything in this movie was totally paint by numbers. Nothing surprising or unique about it.
It did, however, look very nice. So if you are looking for a good looking blockbuster, this is your movie. Just don't expect any emotional or intellectual payoff whatsoever.
I was not all that impressed with Avatar. The story was completely cliched, as were the extremely one dimensional characters, the dialogue was trite, everything was extremely predictable from a mile away. It did, however, live up to the hype in the visuals dept. The world was beautifully crafted, great scapes and creatures, and the 3D was not overdone. The movie will look great even in 2d, the 3d just being a nice bonus. It's just too bad once you look past the surface gloss there is really nothing else that Avatar can offer.