This film is one you DEFINITELY have to see in IMAX 3D to fully appreciate. The landscape and detail of all the creatures on Pandora was beyond imaginative and into the realm of fully creative.
However, to say that James Cameron gets very preachy would be an understatement. It really ruined the ride for me. He decided to give nods to the leftist political idealogies of the Environmentalists and the Hate America crowd and beat us over the heads with it for nearly 3 hours. It was fully disrespectful of the American Armed Forces, and I can guarantee that a good deal of them went to see this.
In summary, if you don't mind another Al Gore lecture, you have to see this as it will visually blow you away.