I'd tend to undervalue the older players. They were great, sure, but part of it is the era they played in. It took less physically to dominate in the 60/70's than it does today due to advancements in training techniques and steroids.
Though you could side-step that easily and just say "best for their era" and determine it by their dominance when they played, not present-day worth.
Rod Woodson should maybe be in the DBs. And much as I hate him, Ray Lewis in the LB's. Also Bruce Smith possibly in the linemen category, and Dick Butkus / Jack Lambert in LB. But your choices are all pretty good.
i know, but i'm not that smart with DBs i know rod woodson was good, and ray lewis should be there, but i just looked at how people performed statisticall, and darren woodson was good, but how much of that was the overall defense and the genius coach, but yeah i agree i need to work on my DBs