@Twirlip,
My own idiosyncratic take on the OP. I don't say too much about God as I believe the word has become too laden with history to serve its real purpose. Nevertheless I have a general belief that there is an infinite good that has no opposite. This is contrasted with various other types of good, which are always transitory or unsatisfactory in some respects.
I am reading about Plotinus at the moment. Actually an edition of the Enneads is on my next Amazon order. His view was that the material realm was not actually evil (like the Gnostics thought) but nevertheless generally unsatisfactory. It was our spiritual goal to remember The One that was beyond all opposites. I think Plotinus would understand evil as the 'privation of the good'. It is basically turning your back to the light, or not acting in your own best interests. But it has no real being. There is an ultimate good, but no ultimate evil. (I will find a reference for this in Plotinus if you wish. I think it is also the view of Eastern Orthodoxy.)
Another spiritual teacher who has greatly inspired me is Ramana Maharishi, the Vedanta sage. He just said straight out that evil was illusory and had no existence whatever. I guess it didn't exist for him, because he was a 'self-realized being' who lived altogether on another plane of reality. When I repeat this here, it sounds completely implausible of course. It seems obvious to us that there are plenty of evil people. But when he says it, it is strangely convincing. (His is the other book on my next Amazon order. I had the Teachings of Ramana Maharishi 25 years ago, but gave it away.)
As for 'devil' - I do think this is a figurative reality. That is to say, there is a real sense in which there is a voice - not an actual voice, but a kind of tendency - which constantly urges you to...well, choose your poison, as the saying has it. I have found in my own experience that this was very dominating at some stages in my life. It usually turned up as addictions, restlessness, and craving. I can say that now in hindsight. It wasn't nearly so clear cut at the time. I guess depending on what kind of habitual tendencies you have, and the kind of environment you find yourself in, these voices/tendencies/urges could lead you into all kinds of mayhem, which is what they enjoy.
Sometimes I think 'the devil' basically gets his kicks via humans. He gets them to live out the stuff he can't do. Figuratively speaking, of course.
It is possible that both God and Satan are symbolic representations. But they represent
something. They are not just imaginary, in the vulgar sense. But the last person I will mention is Martin Luther. I have been reading a book about the theological origins of modernity. Of course, he is writ large. The author suggests, and I think this is true, that in Luther's world, God's omnipotence is such that he also commands the devil as well. The devil only exists on the sufferance of God, who could, if he so wished, cause him to cease existing at any moment. This of course is a deeply troubling vision. My feeling is that he projected his particular vision of God and Satan out onto the Cosmos out of some inner conflict of some kind. But then I really do think Luther was a deeply troubled man. I suppose that is a very controversial thing to say, as far as many Christians are concerned, but I am willing to reconsider it if I can be shown to be wrong. But the recent history of Christianity does not auger well.
For now, I'm sticking with Plotinus and the Buddha.
---------- Post added 02-20-2010 at 08:28 PM ----------
And don't forget the great saying in the Tao te Ching 'the Way that can be named is not the real Way'. So any mention of the Way, the One, or even God, for that matter, is, strictly speaking, figurative or metaphorical.