Natalie Portman deserves an Oscar.
She practically carried off the entire film on her own. Her performance was so good that I actually jumped off my seat at some points and it brought a tear to my eye at the end.
Edit@2011-02-28: Yeay! Natalie got the Oscar! And she actually thanked the camera operator, who definitely deserves the credit for doggedly following her around throughout filming. Bravo!