The great sin is Pride. Satan can get to us through many means, but Pride seems to be where we are usually most vulnerable.
Socialism is all about creating a perfect human society on earth. God, in his infinite wisdom, did not give us that -- but the Socialists will!! They know best, and they have the wisdom to make it happen!
Voegelin called it Immanentizing the eschaton.
I believe Envy is tied with Pride. Just look at the OWS'ers. They have NO pride, but are full of Envy, which makes them violent.
Read Ezekiel 28:12-17 and Isaiah 14:12-14. Is Ezekiel talking about the king of Tyre or of Satan? Is Isaiah talking about the king of Babylon or Satan? How about Genesis 3 - are we talking about the serpent or Satan?