The Hurt Locker, by a country mile. I dug Inglourious Basterds, but I felt Tarantino couldn't keep his dick in his pants - and ultimately it hurt the flick. Moon getting snubbed is ridiculous, especially since Avatar and District 9 got nods. I'd be happy if A Serious Man or Up in the Air won over Avatar, as well.
All in all, it is a pretty terrible nominee list. The inclusion of Precious, District 9, Avatar and Up is totally distinguished mentally-challenged. I would be fine with animation breaking the glass ceiling if it didn't have its own awards category, thereby informing all the other Best Animated Feature Film nominees that they have lost by default.
The Academy is dumb, dumb is the Academy.