I've read all the Ballack versus Zidane stuff, and what I think is that Ballack is a more complete player than Zidane, but he will not surpass Zidane's status in his career. By that I mean Zidane will be remembered for being one of the great players of all time (im not saying whether he is top 5 or top 25) but Ballack will not be mentioned in the same sentence as Zidane in 15 years.
Ballack is a fantastic midfielder, but he does not do flashy, fancy plays. I watched him orchestrate Germany's play in the world cup and he played extremely well swichting the point of attack, finding the open man, making perfect passes and sending crosses in right on players heads.
Even though those plays were just as useful as when zidane juggles over two players and scissors past another, they will never earn the same respect around the world. Individual skill is rated over technical skill. It's wrong, but that's just the way it is.
Zidane, Deco, and Ronaldinho are all offensive players nearly exclusively. However, they do help the defense in other ways. Teams are forced to man mark these players with a midfielder which often results in them playing with one striker up top. That way it still helps the team offensively and defensively.
However, if you had a team with 10 Ronaldinho's or 10 Zidane's, that team would not contend for the world cup. That's what you have to think of when you say a "complete" player. A team with 10 Ballack's or Steven Gerrard's would make a great side, which is why they are complete players.
By the way, Michael Ballack is great in the air, but what I remember most about his heading in the world cup is the chance he missed against I think Argentina. He received a perfect diagonal ball right on his head 10 yards from goal, had a great angle on the ball but headed it about 5 yards wide. Some of you probably know the play I'm talking about.
Vieri's the best header of the ball.Zidane's the best header of opponents.
Sorry for the long post.