Personally, I don't think Gio has been the captain long enough to get voted this high (although, he should probably still be pretty high, considering the competition).
I voted for Pepper. He was never the Flames best player but was one of the leaders for most of his career. He was the captain almost as long as Lanny. Also, he has been a big part of the city and the team alumni ever since he retired.
Plus, how many people can say they were able to stand at centre ice of the Montreal Forum and raise the Stanley Cup while in their underwear? (BTW... Two. The answer is, two people can say that).