Good pick, I loved me some Freddy T. I was actually really hoping he would ball out when he got to the Patriots, but you know, he was 81 by then.
Most underappreciated player in the NFL of all time? Rod Smith. 8 thousand-yard seasons, with about as many quarterbacks, and he was never a guy you heard about on TV. I mean, he had his best year with Griese and Frerotte(sp), not Elway, that always amazed me.
You could also put every o-linemen in the league on this list, guys usually don't get any credit. Specifically the guy that comes to mind off the top of my head is Mitchell Schwartz from the Browns. You might have never heard of him because he's on the Browns, but he might be the best RT in the league in a few years.
Some other guys I would go with... Lamar Houston from Oak, Anthony Spencer from Dallas, Jay Cutler - chi.