I would consider Manning un-benchable, although Ryan is very viable option as well.
I won one of my espn league games 112-6 this week. The other guy hadn't been paying attention since early in the season (still had Ryan Grant starting). Most of his starters were Saints or Packers, both on byes. Only Berrian and Ricky Williams were active, and Berrian got no catches. I had Vick among others.