Call the skill what you will. Stuff, it, that, or other similarly elusive words the game's insiders use to describe the NHL's most sought-after commodity. The bottom line is this: For most of 2010-11, the Bruins didn't have it. One week ago, they got it from Toronto in Tomas Kaberle. And they're better off for it. "It's given us more depth,'' said coach Claude Julien. "It's given us the puck-moving D. It's given us the skill level. But it's also made everybody around him better.'' Like grass-fed beef in steak houses or tablet computers in the business world, puck-moving defensemen are the hottest items in hockey. They're low in supply, high in demand, and even higher in price. Like a player at no other position, the puck-moving defenseman touches the game in the most degrees.