Paul Williams hasn't been mentioned, but I don't think he's ever been in danger of being sent to the canvas?
Williams was hurt in the 11th round vs Margarito and was hurt vs Mattys if i remember correctly but he yet never been knockdown so in that sense i agree 100 percent.
Ward doesn't really get mention about what a great chin he has. Many talk about Gatti this and Gatti that. Yes mostly cause of Gatti pass away and it sucks what happen but still Ward don't get mention alot of having a great chin.
I would agree he came under a bit of pressure when Margo rallied late and caught him quite flush a few times, but he took the shots well given how late in the fight it was.
My vote goes to Winky. Never been stopped, rarely stunned and just look at the names on his resume. Also stuck his chin out and took bombs from Shane Mosley and laughed at him. And yes, even a slick boxer like Winky has been hit flush plenty of times.