This was a tough one to vote on. Fights off the opening faceoff are so rare (much less 3 fights) that it was hard not to vote for the Devils-Rangers rivalry. It was clear the Battle of the Hudson is alive and well. I also thought the Bruins-Flyers rivalry was great. They are truly the only 2 old school teams in the NHL today. the January 22nd game between the two teams was one of the best games the new NHL has seen.
Despite all of this, I had to go with the Battle of Pennsylvania. The hatred and animosity between those teams surpassed the other rivalries on the list. When the rivalry reaches a boiling point where superstars like Crosby and Giroux are going at it, or coaches are about to climb over the boards to get at each other (reminded me of the infamous Sabres-Senators brawl a few years ago) you know you have something special. I think what makes this rivalry the best of the season was that it carried over into the playoffs.