Enemy.
Trailer here:
http://youtu.be/FJuaAWrgoUYBest movie ever... I lie... I couldn't say that with a straight face.
I went with my SO to this movie as the trailer looks decent, but what we ended up watching, wasn't what the trailer depicted. The movie itself is a decent flick, and it's a very different type of movie than most. A psychological thriller.
The reason I post this isn't to recommend it to everyone, but more to see what everyone else thought of the movie. It's a Canadian film shot in Toronto and has some Canadian actors in it.