Spoiler alert: The final two players on this list are the best in the universe at their respective positions. Nick Mangold is simply the best center in the league, without dispute.
Physically, Nick is a specimen for the position. He has the strength to hold off the biggest men in football - the 3-4 nose tackle - with consistency. Not only does he hold them off - he pushes them around in the run game. He is also athletic enough to make blocks downfield.
Of course, playing center has a lot of mental aspects to it. Sanchez leans on Nick to help make the right checks and line calls. When you combine this combination of physical ability and mental preparation, and sprinkle in the fact that he is easily the funniest guy on the team, there simply is no better center on the planet than Nick Mangold.