Visually, "Avatar" is beautiful, a work of art; Pandora is a fully-realized, populated, functional world - a world of wonder. Luminous plants, fungi, floating seeds and exotic animals and flying reptiles add visual grace notes to the symphony of wonder.
The plot doesn't disappoint, either. The story of greed and the destruction of beauty is universal, and has echoes on our own blue world. The characters are realistically acted, and the CGI is seamless enough that you cannot tell where reality ends and animation takes over.
Go see this film - do not miss it. See it on the biggest screen you can, in 3D - you won't regret it.