Excluding Mendenhall from this list disqualifies it.
Yes, he fumbled in the Super Bowl, but #1 they aren't even there without him and #2, it was on the legs of Mendenhall that the momentum had even begun to shift. I will argue that if Pouncey were healthy that the Steelers win that game. Doug Legursky was shoved right back into Ben's throwing motion to create the pick-6 and Legursky missed the pull on the block that gave Clay Matthews a clean shot at the ball, and if he were blocked by Pouncey, the hole for the first down and 7-12 more yards was there for the taking.
In the first 4 games without Ben when he had 411 yards and 4 TDs. In the AFC Championship vs. the Jets, it was all about how the Jets beat 2 of the 3 AFC QBs that had represented the conference that decade (Manning, Brady and Ben) - but they came out running it and Mendenhall had 90 yards rushing in the first half alone where they got the 24-3 lead. He had 4 TDs and 230 yards in that post season run.
His ACL tear in the final game of the 2011 regular season was devastating. I always thought the 2011 Steelers were better than the 2010 version, but the injuries and the last second loss to Baltimore that prevented them from winning the division was killer to what I still believe would have been a Super Bowl run.
He never came back from that ACL injury, but I would take his 2009-2011 over Barry Foster's 1992 one-year wonder and being a $hit teammate who only tried when he wanted to.