Coming home from Avatar -- a wonderful movie experience -- I found myself thinking of Ray Bradbury's story "Here There Be Tygers." The last time I read this story may have been decades ago, and I don't think the Wikipedia entry gets the plot entirely right, but as I recall the plot it shares a number of features with Avatar.
In "Here There Be Tygers," humans arrive at a wonderful planet where they are made fabulously welcome. But they are there to extract natural resources, and when they try to drill in a particularly idyllic spot the planet -- which we now learn is alive, and sentient -- destroys their machines, and all but one of the humans leave, I think because they are forced to. In the last moments of the story, the narrator (one of the people departing) catches a glimpse of the only human who stayed, still enjoying the paradise the planet offered to those who did not violate her.
Avatar's plot isn't the same by any means. But the idea of humans as savagely violating the natural beauty of a world that is self-aware is common to both the story and the film. I don't mean to suggest any improper influence, but rather just that artists do naturally influence each other, and I wonder if Bradbury's story influenced James Cameron. I remember finding Bradbury's story magical when I read it long ago, and Cameron's movie at its best is magical too; it would be nice to think that they are linked across 5 decades.