Ego - The most superficial and temporary part of ourselves yet the one we most commonly identify as "I". It see's itself and the physical body as one in the same, though it is not necessarily. It is the sum of individual biology and personal experiences and is concerned primarily with survival and personal satisfaction --though the ego's very nature is ironically often counterproductive to both of those ends. Spirituality is particularly concerned with overcoming or seeing through this aspect of the self.
Inner Guide (the Higher Self) - An extension or "face" of God that could be seen as a mediator between the ego and God. It is the part of ourselves that has perhaps eternally existed and reincarnated in different forms, if reincarnation is true. Having much more wisdom than the ego, it is always calling us to meet our highest potential on this plane of existence. One could say this is the "personal" extension of God which we can have an inner dialogue with (which may partially explain why there is so much disagreement on what God supposedly says). The more we peel back the ego, the more the higher self shines through.
God (the Ground of Being)- This is the part in which all that exists is inextricably connected. It's essence is pure energy and pure consciousness. To experience God is to experience the deepest core of our being which is simply an awareness that beneath the ego, and beneath even the higher self, we are all fundamentally one thing. The ego may have some awareness of God via the higher self, but often taints it with the ego's own thoughts, desires and traits to give divine validity to it's own selfish ends.
With the understanding of the God above, perhaps a more accurate visualization would be the following :
I realize the essential weakness in this theory is that I am working through the "ego" to postulate about these different levels of the self, but take it for what you will.