Seems that its becoming painfully obvious that while you look at an image of an Avatar they are beautifully different from a human, but at the same time its hard to lay your finger on just what makes them different "Ears aside obviously".
I think dave, that.. with your's it needs to have more of a ...'unibrow' structure to the eyebrow area....i think the cheekbones need to be shaped a bit different,...More defined, but not more prominent...if that makes sense.
i think the nose is getting there... But still needs a bit of work.. if you'll notice the avatar nose still has the.....almost sharp curve between the top edge of the nose and the front (would be the wet fleshy part of a cats nose) area, and the front area is a bit broader and flatter then a human nose.
Unless you're going for the Sigorney Weaver look anyway