This was pretty masterful filmmaking from top to bottom.
Procedural yet very suspenseful. Knowing the ending doesn't do any disservice to the path that got there and Boal and Bigelow's careful and convincing depiction of the decade long hunt for bin Laden, the woman that persevered in order to find him and the men that ultimately killed him.
Like The Hurt Locker, Zero Dark Thirty is very intimate even though it's dealing with a such a larger scale event. It's cinematically stylish without ever drawing attention to itself and instead draws the viewer in closer. It's a stunning film.
ETA: I suppose I should comment on the torture element since it's been such a controversial, hot-button issue. I feel like the swarm of commentary about it has been overblown, overstated and utterly ridiculous. Not only is it a small part of the film and story it doesn't shy away from the truth about its use or the validity of it (or lack thereof).