This movie is "The best".
Storywise - Very standard sci-fi
Visuals and conceptualization - 11/10
The alien nav'vi world is beautifully shown and very well rendered. Nowhere does it look fake. After all it's done by Weta Digital, the same dude responsible for the wonderful Lord of the Rings movie.
Unfortunately I cannot find any good wallpapers of the nav'vi world anywhere. Just the main characters.
The Nav'vi inhabitants comceptualization is majorly influenced by...
1. African culture (the look, the rituals, the lankiness & height of the characters)
2. Native red-Indians (indicated in the scene where they thank their world for giving the flesh of the creature that the main character kills)
3. Underwater creatures. This is very apparent every where in nav'vi, the colours used, the transparent creatures, light emitting from them...beautiful!