I think Robben ..ofcourse if he doesn't get injured again like he always does.
The reason is because Netherlands don't have much pressure on them and Robben thus doesn't have pressure on him. If he gets them to the semi final, it's like an excellent job to everyone and will exceed expectations. Messi , however needs to do a lot of work and no matter how much he does unless he wins the WC, they will say he is not the star of the WC. Cristiano Ronaldo doesn't have a good team to support him ( at least not good chemistry) . Most probably, Rooney, Xavi, Robben ...
The Germans are not at their best player-wise. Next two three years they will have a great team, but right now they don't have a quality player to shine in the WC. They will have to count on being organized like they always do.
Other random players that will attract attention are Krasic , Suarez, Hamsik, Lloris ( he will have to do a lot of work to save France's ass

).