For me, it was Haywire and Moonrise Kingdom.
With Haywire, I honestly went in expecting a very trite and mediocre spy thriller with nothing particularly unique or inspired.
What it ended up being was one of the most inspired and best directed spy movies I've ever seen. Soderberg's shot selection and color palate was absolutely beautiful, the score, in conjunction with the editing created frantic and almost musical-like action segments. And the fight choreography was by far the most realistic, brutal and beautiful fight scenes I've ever seen. It makes the fight scenes in Batman or Bourne look almost silly and animated.
I knew Moonrise would be good - I'm a big Anderson fan - but I truly wasn't expecting him to craft without a doubt the best film he's ever made; every single shot in the film was a piece of art, every selection of music was inspired, and the writing contrasted and conjoined the differences between love during childhood, adolescence and adulthood better than I ever thought possible withi a singular narative.