I voted Iniesta because of the current heirarchy.... Then I remembered that Valdes is ahead of Iniesta.
I think Iniesta would do a good job as captain, although he is quiet and barely makes a noise in the media, he is level headed, and is respected by the whole football community. The only thing that Iniesta needs to to be more vocal.
Pique is the obvious choice. He has every quality to be a good captain. The most important one... he has enough upper body strength to lift lots of trophies in the future
So
Iniesta
Pique
Valdes
Messi
Dani Alves should be somewhere in there too