Gilles Villenueve (1 little known race for Mclaren, I think)
Niki Lauda (Champ for Ferrari x2 and Mclaren x1)
Gerhard Berghar (Well known in red, I think he drove Mclaren too)
EDIT: Kimi of course! He won the championship for the Scud back in 07 after coming close with Mclaren before that.