Returning to the airport after a Liberty Fund conference a rather famous legal philosopher who was in the front seat of the van turned around to the rest of us passengers and said "I take it that all of you knew this character Gordon." Several of us were economists and political economists so of course the answer was yes. Tullock was typically intellectually engaged throughout the conference and challenged many a received wisdom. He was aggressive, but brilliant. I think that sums up his entire career.
I have been blessed in my academic career -- both as a student and as a colleague to have been exposed to Gordon Tullock. It will be impossible to replace Gordon Tullock, but I hope our department will honor his career by maintaining that fine balance between intellectual irreverence to established opinion and refined and sophisticated argumentation in economics, politics and the social sciences.
Leonard Liggio has a great post on Tullock's retirement.