Vieri is definitly the biggest flop, Jankulovski also I expected a lot of him. And I didn't saw that anyone mentioned Robinho - I mean he was the main story of the transfer market, people were expecting wonders of him, but nothing, got few goals scored, even Nonda got few goals.
And I'm not sure what Viera is doing on the list, at least he's playing regulary, and had few raelly good games, and even scored goals, he didn't deserve to be on the list.