There are many good reasons to go see Avatar in the theater, especially if any part of you gets excited by visual effects. Despite the fact that it looked under-impressive in the trailers, on screen and in 3D the eye-candy is like nothing you've ever seen before. The world that James Cameron created with Pandora is totally unique and immersive. That said, the story didn't really work for me. It's pretty cheesy in places (not a huge problem) but there is absolutely nothing surprising that happens in the film. You can see every plot point coming from forty clicks away, and there are lots of plot points in two hours and forty minutes.
I see quite a few similarities with this to Titanic, and not just the music score that James Horner essentially ripped off from himself; the good guys are all good, and the bad guys are spectacularly bad. Stephen Lang in this makes Billy Zane from Titantic seem like a complicated character. And like Titanic, I think Avatar, despite how cussing amazing it looks, will age poorly.