I really fancy Brazil to do in the World Cup what they did in the Confederations Cup last year, probably lose or draw one group game but still get to the knock out stages, and be none too convincing in the wins. Then steamroll everyone on their way to the final. The only thing that might count against them is their defence, as already stated, and the fact that so many of their top players are playing a lot of games this season, can Ronaldinho keep going at the pace he is at? Can Ronaldo keep up the improvement in form? Even if they don't, their reserves tanked Argentina in the Confederations final last year, and their second string has to be stronger than most teams in the World Cup itself, so they definately have plenty in reserve. Who is going to replace Rooney for England? What if Owen is not fit?
If you're looking for a dark horse, go with the Dutch or Italians, both topped their groups without any problems, and are playing with a unity not usually seen, certainly in the case of the Dutch. Van Basten has got a team of not so famous names playing attacking, fluent, exciting football.
I'd quite happily kill if it meant Ireland would play in Germany, but I think I'll settle for watching the boys from Brazil play football the way we want it played, not the way Sky tell us it should be played