WRONG! He got TKO1'd by Derrel Coley. But still impressive. http://boxrec.com/list_bouts.php?human_id=235&cat=boxer
You can't deny the iron chin that is Mosley. He's pretty much a chin with a body. It was a 40 y/o Mosley that still went the distance with pac. Pac's a monster, not many that could walk through pac's punches. Froch definitely gets a nod, for sure.
I think the OP means today's fighters. Toney and Mosley are shot and their punch resistance has decreased. Rios is also beginning to decline as well believe it or not. His punch resistance is declining. I'd say the best chin in boxing today belongs to Marcos Maidana.
Of all time? I'd certainly have to give Ali a shoot out. The punishment he took from Foreman and Frazier was beyond human.
oliver has a great chin, cant call it the best because of his slack resume. the guy fought in 1 of boxings best eras , the late 80s and 90s and he never fought holyfield foreman mercer ruddock morrison tua bowe witherspoon tyson or even shannon briggs, jermey williams or bert cooprt level bombers he has 2 or 3 guys on his resume who could hit Lewis, Bruno had he fought his share of those guys, his chin may have been checked sorry, facts are facts :deal
the punches from shavers for 15 rounds at his age/ end of his career were unreal he took...alot of people say that did most of his long lasting damage . he took a hideous beating from holmes for 10 rounds without going down..a prime holmes and an Ali that shouldnt have been medically cleared to fight