Any of the big boys, Argentina, Brazil, Germany and Italy can win. Like I said, there has never been a World Cup final played without at least one of these teams being there.
People hype Spain a lot. And yes, they have a great team... but it's not the first time they have a great team.
And honestly, who would you rather play against: Spain or Argentina/Germany/Brazil, or even Italy? The answer can be found from the World Cup history. It's not a coincidence... it's not only about the talent, it's also about the "culture of winning" that all these four big teams have. Spain has NEVER won even one medal... they one 4th place. And that was 60 years ago.