From a lot of angles, Peyton Manning is the greatest quarterback of all time. His second Super Bowl win, however, came in decidedly un-Peyton-like fashion, with Manning riding in the wake of an all-time defense while doddering well below replacement level for most of the season. Perhaps this is karma, a just reward after a career of — with a few exceptions — being shackled to some of the worst defenses ever to run deep into the playoffs.