I'm going with Giroux because of his intangibles.
Seriously, it's really close, but I had to give Claude the edge. G has been taking an absurd amount of face-offs, PK's, runs the PP, and has had one of his better years defensively at what I think is a more valuable position.
I don't know where to find an updated version of it, but there was that player usage chart going around sometime in December I think, and G's minutes were clearly harder than any other top center in the league. I'd be willing to bet that Voracek's minutes, who were easier, are real similar now that Berube has decided that the 4th line deserves more offensive zone starts than anybody else.