Spain won't win the world cup imo. I think they'll do well to get out of the group stage - especially if the dutch beat them in the first game which is a very real possibility. Plus if the dutch do beat them then they'll most likely face Brazil in R16.
I don't know for me Spain don't have that same aura that same magic that they have 3-4 years ago. So I think that the 2014 world cup will be a step too far for the group of players that won in 08, 10 and 12. Even with Costa as their main striker.
I may be wrong about Spain but I can't help the feeling that their era of domination on the international stage is coming to an end. But it won't be 40 years before they win another tournament because of the class of player coming through the ranks. So they'll be competitors in every tournament for a long time to come.
For me I just can't look past the Argies and Brazil.