The first reviews are trickling in and both the Hollywood Reporter and Variety are praising the movie. HR comments "movie magic is back" and thinks repeat business is high http://www.hollywoodreporter.com/hr/film-reviews/avatar-film-review-1004052868.story while Variety says James Cameron has delivered a film with "universal appeal" http://www.variety.com/review/VE1117941773.html?categoryid=31&cs=1. We'll have to wait and see but it sounds like Cameron has delivered.
An update-Another 4 star review-this time from Roger Ebert who compares viewing it to seeing Star Wars for the first time http://rogerebert.suntimes.com/apps/pbcs.dll/article?AID=/20091211/REVIEWS/912119998 (and Ebert may not be far off as Cameron himself has revealed plans for two sequels. The Star Wars of 2010s?)