Just came back from watching it, and WOW!
I didn't think anything like this is possible, and I can't imagine the effort it takes to create something as complex as that, technically. And I was wondering what an army of the top animators, CG artists and sound designers worth half a billion $ can do.
This movie takes CG to a whole new level. As someone else said, I now understand how people felt in 1933 when they first saw King Kong.
As far as the actual story/plot line, I could barely care less. Poor and full of cliches, but even if there was no plot at all, I'd still watch it.