#1 Rio Ferdinand (2002-2014)
All the previous entrants on this list certainly merit their inclusion but what sets apart Ferdinand is his class and elegance which is a rarity in an English defender.
Of the current English defenders, John Stones is perhaps the defender most comparable to Ferdinand, but Stones has a long way to go before he can match Ferdinand's achievements in the game.
On joining the Red Devils from Leeds in 2002 (which further increased the hatred between the clubs) as a fresh-faced 24-year-old, Ferdinand would become the mainstay of 3 different title-winning sides at the club: the 2002 vintage (Beckham, Keane etc.), the 2006-2009 side (the Rooney and Ronaldo era) and finally the 2012-13 team (Van Persie).
Along with Vidic, he was half of a partnership which led United to 5 titles in 7 seasons and which became one of the best sides in the world. His silkiness and calm on the ball perfectly complemented Vidic's more physical approach.
Ferdinand can lay claim to being one of the best centre-halves in the club's history and certainly the best they've ever had in the Premier League era.