Manuel Pellegrini
Manuel Pellegrini's last stint at Madrid was an unlucky one. While he was the one who brought in Cristiano Ronaldo to the club, the fans of the club and the media have conveniently forgotten what he did to Real Madrid.
The Chilean had a successful spell at Manchester City winning the Premier League title once and the League cup twice. His influence on the dressing room has often been lauded by a lot of his former players but he's also the kind of manager who gets his players to perform at a level higher than most.
He does have the experience to manage a big team like Atletico Madrid and has the impetus to get one against his former employers. Pellegrini's playing style, however, isn't something Atletico players are used to and could take some time to understand his passing game.