Avatar depenRAB on how much money it takes. If it doesn't slow down, and it is showing no signs it is, then I doubt the academy can ignore it. Especially if it gets to or near titanic levels of money.
Having said that I think Kathryn Bigelow will win best director, mainly because no woman has ever won it before, and Up in the Air will win best picture. Up in the Air is so much in the style of a classic Hollywood movie, like a cynical 21st century version of It's a Wonderful Life, I can't see how Oscar won't love it.