The plot of Avatar in 3-D (such as it is) can be summed up as “Military Dominated by White American Males bad; everything else good.” Just look at the special effects and ignore the “story.” There really isn't one.
So Earth looks like the WALL-E planet on a bad day, but somehow Sigourney Weaver can still get cigarettes, made from... what? Wait; I wasn't supposed to question that. No eco-tourism from Earth. We're evil — run by white males, so we only want to despoil, get it yet?
The special effects are very good. They really created some interesting alien landscapes, plants, and creatures. Too bad they spent all of their money on that stuff and didn’t invest in hiring a writer. Oh well — maybe in the inevitable sequel...