I've never especially liked Club America, a Mexico City soccer team owned by the Televisa empire. The side often wins and projects an image of power and status. It comes from the mammoth capital, where much of the country's political and economic power is still concentrated. Club America also fields well-paid imports and controversial figures like Cuauhtemoc Blanco, a prolific goal scorer, but bad teammate, who deserved to be left off of the 2006 World Cup squad.
Due in large part to Televisa's long reach, Club America is popular in virtually every part of Mexico - even in Guadalajara, the home of Chivas, a team that only fields Mexican players.
Here's my take on Club America's popularity in the provinces: http://www.eluniversal.com.mx/miami/24702.html