Without dissecting the back 4...
I have to say that hands down, the best goalie in my opinion (in the world) is Neuer.
That being said, Germany's back 4 is abysmal, and I fully expect them to lose to a fast team that can control possession - i.e. Columbia and especially Brazil. France could even knock them out if Benzema plays at his peak.
As for Belgium, they'll most likely embarrass Argentina. Argentina doesn't have the defense that Belgium has seen in the first 4 games that they've played. Now you may look at me and say... Ken, do you mean to tell me that the US, Algeria, Russia, and South Korea all have better defenses than Argentina? And the answer to that question is no... but they also won't hole up and play 8 in the box the way that all of those teams played. Argentina will try and play to their strengths - their offense. They'll be open, and Belgium should be able to capitalize on that.
Not that it matters who wins this game, IMO... I've been predicting a Columbia vs. Netherlands game for a little over a week now, and still believe in this prediction.