Keanu Reeves
When I realized Keanu was in it, my first reaction was "Oh noes!".
But after watching the movie I actually consider this one of his best performances. Not by much maybe, but at least he's actually doing some acting and interaction with the other actors, and especially with Charlize of course.
I like The Matrix, but I wouldn't call what Keanu did there acting.
My favorite movie with Keanu is otherwise Constantine, mainly for the movie itself.
I'm sure I'm fairly alone about this opinion, but there you go.