Spain or Brazil, on current form Spain, but Brazil have for decades been a bit crap up until the actual competition, we'll have to see.
At the moment Spain are incredibly strong but still have suspect defensive frailties, Sergio Ramos for one, so so easily passed last night as they made their first goal. He's a joke of a player, frankly in the Euro's there wasn't a huge amount of talent up against up on that wing, Brazil and maybe Argentina can give Spains right back a MUCH harder time and could prove to be the difference.
But then you've got to factor in the possibilities of injuries and realise anything can change before then, Xavi or Fabregas get injured and they'll have some major firepower missing. Fabregas changes that side everytime he came on, and Xavi is very good defensively also where the rest of the midfield aren't exactly great in that area and I haven't seen Senna playing for Spain recently.
Brazil need a Kaka firing on all cylinders, at the moment he's rather crap at Real.