Interesting post Teuto. In your post you're describing two forms of greed. 'positive' greed and 'bad' greed. I wouldn't put it like that, rather desire/ambition and greed. At it's core those two driving forces are the same but different at the same time. Greed is a state of being where you can never be satisfied, always looking for more. In my opinion greed is always 'bad'.
Ambition/desire on the other hand also drives you to improve but it's easier to balance out with moderation.
RE: This Greed Of Ours!