Saw Avatar last night with my mom. We both liked it overall, but...it was too long by about 20 minutes or so. Visually spectacular and brought 3D to a new WOW level, doing so without cheesy effects.
However, the last portion of the film which simply became some sort of battle royale was way over the top, too much Terminator type of battle that destroyed avatar lives and the Pandora environment in its wake. Way over the top, and it brought down the movie overall.