I am a believer in Jesus Christ, and I didn't see much wrong with Avatar. Sure, it does not in any way represent Christianity or anything that we know for that matter, but I reckon that was the point of making the movie on some strange planet in the middle of the universe, and not on earth...
The bible was intended for man and speaks about man. Not about intelligent beings on other planets. Who knows how God would reveal himself to other people? If you believe in God, then don't put him in a box. He is God afterall.
In my opinion, take the movie for what it is, a movie. Nothing more, nothing less. If you don't enjoy it, walk away and no harm done.