I think Spain is the strongest and the deepest squad, they won Euro 2006, and a lot of Spanish players are doing big things all over Europe, (don't leave, Fabregas!). And I wouldn't say the Wold Cup is more physical than the Euros, besides, a lot of Barcelona players deal well with physical / perceived physical play. I would be very careful even trying to touch a player like Xavi, he might go down. Looking forward to seeing the Netherlands too, they have a good squad, and Robben and Sneijder are doing big things in Europe, so that can only be good for the Netherlands. I'd like to see a confident display from the Netherlands, because they have the talent. I wouldn't say they are favorites though.
Argentina? England? Come on guys! Some big question marks there. Especially Argentina, they may have the best player in the world, but that's it. I mean, on the big stage; they have decent players, but that's it.