For me, there was Joe Wark then everybody else. It's difficult to explain to anyone who didn't see him play just how good he was. Perfect timing in the tackle, crunching but fair, great game reading skills,precision curled passes up the left touchline time after time, picked up his first yellow card after about 15 years in the game. And to cap it all, used to entertain with his ball juggling skills if there was a stoppage in play.
Tom Boyd started off in the middle of defence playing a sweeper type role, but really grew into the left back role when he became a little stronger and faster. Another one who had great game reading skills.
Then there was Derek Murray whose main skill seemed to be standing 3 yards too far off his man and never quite being in the right place.