I know Vaughn Johnson always gets a quick mention in the LB conversations but he really doesn't get enough credit. He was an absolute beast and could thump you with the best of them. He was over shadowed by the other three because he didn't make the highlight reels but he was a major force and he was feared throughout the League.
I thought i remember when the NFL did the top ten show, when they did the Line backing core, Roger Craig said the first time Vaughn Johnson hit him, he went back to the huddle and told the Oline, Don't ever let that guy hit me again...