Now fair does the story is simple, it is simple in the way any other film in which the main char joins with the indigenous people and changes sides to fight against their oppression is, take Dances with Wolves, The Last Samurai, The Mission, etc etc ad infinitum, can be. The story was good enough to keep me watching, that countts for something, and yes I did end up rooting for the Na'vi.
Most of what this film was about was the tech, and no I don't mean the mech suits, they just looked like rejects from the Matrix, and if anyone comments about exposed pilots look at the matrix ones first, ahem. Anyway, yes the technology behind this film is what makes it such a spectacular viewing experience, the total immersion given by the 3D was superb, usually in a 3D film it gets over empbasised with things that come straight towards the screen and make you want to duck out of the way, with Avatar, there was none of that, it just helped build the impression that you were there in the world with them.
Now, the creature designs were cool and loved the complex idea of how they could connect with the environment in a very litteral sense. One thing that I found a little odd in retrospect was that the majority of creatures had 6 limbs yet the Na'vi have only 4 a minor detail but bleh.
I 'd happily go see Avatar again, there is too much to see in one sitting I felt and if you feel sceptical about going to see it, put it all out of your mind, clear your head, don't over analyse it , sit back, relax and get swept away.