Greetings... interesting thread.
For me the ego is 'me' where-as the spirit is the 'I'; as in the purest 'I am', the purest state of beingness.
I don't profess to know a huge amount about this but I have always likened the ego to the more animal instincts we have to deal with, and in these, desire (jealousy, envy etc etc) is the most destructive when you are trying to progress to a more enlightened view point. Desire, or wanting something, is often the catalyst for life's troubles. Need is not desire, the body needs water to survive, and the ego directs your actions to obtain water, thus the ego is a good and worthy companion, however if the ego directs you to murder your neighbour just to get a glass of water then that is where the ego destroys your progress (not to mention the other persons).
Survival on this planet requires an ego, but in my opinion, enlightenment is a state in which spirit has attained mastery over the ego. The ego becomes a tool to be consciously used rather than it using and directing you. Destroy the ego and you destroy your ability to function in this reality.
My 2 pence anyway.
