"Avatar" is worth seeing once for the eye candy. However, beyond that it's every other noble savages saved by the civilized guy who learns their ways movie.
Why didn't the humans just *ask* for the unobtainium? They tried to trade for it by offering stuff the Na'Vi didn't want (an English language school? Why?). Why didn't the humans just go to the Na'Vi, and say, "Hey, our people desperately need this gray rock that you have no use for. Would you let us dig it up if we promise not to hurt your God-Tree?"
Also, why does every creature on Pandora have three sets of limbs except for the Na'Vi who only have two? Is it because lanky blue girls in moss bikinis wouldn't look as hot with an extra set of arms?