Hubby dragged me to Avatar too....LOL.

We took the kids and even they sat through it so there was enough to keep them facsinated.  I think it was all the pretty imagery that kept Haley enthralled.  She got most of the concept, though at the end she asked me "why the humans wanted to tear down the tree", so she didn't get the main premise.  So I explained it to her this way - imagine if aliens came to earth and found out there was huge piles of oil under our city and decided we had to move or they wold burn down all of our houses and make us move.  She got it.
Alex - at 5 years old - didn't understand much of it but the imagery, unique animals and stuff kept him sitting too - he did not understand that the humans were not just "dreaming" all of it when int he stasis boxes...but hey.

It had a nice message, wasn't too predictable, and although I found it a bit long there were a lot of neat things to look at.

Can't wait for the Alice in Wonderland movie - love Johnny Depp!!