There are a few. First and most obvious would be my father, who passed away in 2007 at the far too young age of 56. Even though he wasn't a big strong guy, just avarage of build, he was a true man. If I turn out to be only half the man he was, I will have succeeded in life.
Then there is Chuck D of Public Enemy. One of the things he said is "if I can't change the people around me, I change the people around me.'' That has always stuck with me as a good philosophy to live by. To me it means that if I can't positively contribute to those around me, I should surround myself with other people.
And that also brings me directly to my friends. Since I apply the above to them, it also means that my friends contribute positively to my life. It works both ways.
And my two daughters have influenced my life tremendously. Not by what they say or do directly, but because they have given me so much perspective.