The most obvious answer is that Grant Munro is the best we have produced he managed to continually improve and make through the leagues and at different levels, then go onto captain our club he would go down as one of if not our best centre half we have ever had and lets not forget that goal he got against celtic in his last season, I think Harry Kane would be claiming that if he could. Captain, leader and decorated champion.
Next would be Nick Ross just due to his overall work rate and contribution he made to the team through-out his time playing for the club not to mention THAT goal against Hearts he has to be number two.
Christie would be next and probably had he stayed with us longer he could be the best however he left us after not very long in the first team.
Lastly would be polworth, I mean if he left tomorrow would anyone really care, work rate questionable, attitude questionable, good at dead balls sometimes not exactly a player people could say has done much to make fans remember him either apart from his countless complaints at his teammates for messing up or time after time losing the ball and just standing there watching it instead of getting it back.