The only problem with Avatar is that it will be projected as nothing but another epic sci-fi or fantasy movie, and thereby passed up by too many main stream movie goers. They will be missing a huge ground breaking experience in movie making. See the 3D version if it's not sold out.
2hrs and 40 minutes of sheer excitement, bewilderment, wonder, all centering on a very effective if not predictable love interest and story line. Who cares if it's not that original... it's not like we didn't know how Titanic would end.
Overall, I can't recommend this movie enough, especially to those who wouldn't normally see this genre of movie.