I believe it is a great quality to posses. Greed is an acute desire for perfection; greed makes us strive for perfection, and it gets us closer to it. Greed makes us work harder, it makes us reach a potential that was always within us, but that we never explored. Communism is the biggest failure of the past century, because it was based on an ideology which suppressed greed -- greed gives individuals independence and confidence.
I'm greedy for information, people, energy, love, nature, adrenaline, happiness, life. Greed is not a severe sickness, greed makes us different, and better.