According to Goldman Sachs (not your best football forecaster!)
http://blogs.wsj.com/moneybeat/2014/05/28/goldman-sachs-predicts-the-world-cup-winner/
Top 4: Brazil odds 3/1, Argentina 9/2, Germany 11/2, Spain 13/2.
Then comes a group of contenders that can cause a few surprises: Belgium 16/1...