As a young kid: Bill Gates and Steve Jobs
As a young adult: John Warnock and Kai Krause
You probably know the first two :) And though they might be a bit obvious, what can I say? As a kid, they were gods to me.
I believe in meritocracies, the power of ideas, and the value of will. That's what these gentlemen, and their achievements, represent to me - that's what they taught me.
Looking at that now - as a slightly older adult - there's an interesting, consistent polarity (along an entreprenurial axis) between technology vision and creative vision, respectively, that has been attractive to me: Gates v. Jobs and Warnock v. Krause. And though I don't mean, in any way, to diminish the heroes of my youth - who have undeniably proven themselves as adept technocratic giants, agile business leaders and humanitarian luminaries - John Warnock is 10 times the technologist Bill Gates will ever be, and Kai Krause is 10 times the creative visionary Steve Jobs will ever be. What can I say? Success (and even leadership) is not the same as vision.
Don't believe me?
That's OK - my beliefs don't require that you do :)
I do find my value system evolving, though, as I've gotten (slightly) older, particularly now that I have kids.