Avatar VFX supervisor Joe Letteri said in his acceptance speech that Avatar was "about seeing the world in new ways," he said. "And just remember the world we live in is just as amazing as the world we created for you." Backstage, Letteri said he was responding to the idea of the post-Avatar depression phenomenon. "We took things out in the world and made them bigger and shinier," he said. "All our inspiration comes from the real world."
Backstage the VFX winners insist that the actors delivered the performances, and they built on them, used them as a foundation. UPDATE: Here's more at THR.
Here's my long flip cam interview with Letteri, and a quickie from the red carpet: