Underrated : Preeeeetty much every young player juve snaps up and sends on loan, Camoranesi, Gasbaroni (special mention.)
Overrated (current form): Nedved, Zebina, Mutu, Del Piero
Vieira isnt overrated, he just probably has a very nice contract in which he has to play this this this amount of games. I doubt Capello wouldve signed Zanetti if he thought that Vieira was doin an A-ok job (still, why zanetti).
and goodness, Abiati isnt underrated, but we cant bloddy hell play 2 keeper altho by the looks of it, abbiati would score alot more that zlatan (cheap shot, i know haha).