My wife and I finally went to see Avatar and we really enjoyed it. The 3-D effects were a lot more subtle than I expected and the special effects were very impressive. James Cameron has created an amazing world. The portrayal of the military was a little heavy-handed, but overall I thought it was a fun movie. It definitely didn't feel like it was almost three hours long.
If you liked the movie, you might also like the book Avatar: An Activist Survival Guide by Maria Wilhelm and Dirk Mathison. It's described as "a confidential report on the biological and social history of Pandora." Loaded with color images throughout its 203 pages, it provides in-depth descriptions of the alien moon's geology, atmosphere, animals, and plant life, as well as a look at the indigenous Na'vi people. The book also features information about the human vehicles and weapons from the film. A glossary and a Na'vi-English dictionary rounds it out, making this a great resource for fans of the movie.