floyds chin is underrated. the 2nd punch Mosley landed was set up perfectly and probably would have had most dudes out of commission. Floyd recovered like 5 seconds after it happened.
It's the only way I see Floyd losing, he can't be outboxed by any boxer in the 140 - 160 lb divisions.
Kahn or Pacquiao maybe, only because of their speed and the fact that Floyd hasn't got that one shot KO power.