It has its flaws, for sure, but I forgive them because as a whole, it's an amazing film. In the past, whenever there were entirely CG characters on screen, the reptilian, primordial part of my brain subconsciously picked up on all the subtle inconsistencies and unnatural movements, alerting me in a very visceral way, as if it's telling me, "Hey - that character's computer-generated". And that sensation would run like a nagging loop in my brain, making it hard to fully enjoy the movie. No matter how great the effect has been, it has always looked computer-generated.
Avatar is totally different.
The nuanced expressiveness of the CG Na'vi characters is absolutely spectacular, and they are the most convincing, organic CG characters ever. This, and due to the fact that the 3D is totally unobtrusive yet completely convincing makes Avatar the most immersive film I've ever experienced.
Sure, the plot is to some extent, an amalgam of a lot of other genre movies, but how many awesome movies that you love are wholly original properties unto themselves, owing nothing to other films and totally non-derivative? Yeah, not many. In short, shut up, haters. The flick is good.
And that alien chick is smoking hot.
Too bad we'll all have to see folks crow-barring themselves into skimpy Na'vi costumes at conventions for the rest of our natural lives.