On Friday, I mentioned that Christians do not universally agree that Satan, Lucifer, and the Devil are all the same people nor that there even is a personal, sentient enemy Devil.
Most of the modern narratives of Satan as a fallen angel come from extra-biblical texts, especially John Milton's Paradise Lost and Dante's Divine Comedy. From those stories, we infer support into some biblical passages, particularly Isaiah 14 and Ezekiel 28. Unfortunately, those are explicitly referring to the kings of Babylon and Tyre, respectively. While they could be metaphorically discussing a personal Devil, I see that interpretation being quite a stretch.
In fact, the original use of the term satan was anything or anyone that challenged one's belief. Satan was "the Other" in sociological terms. From this view, any description of Satan as a person is more of a personification of internal and interpersonal struggles and temptation. In my opinion, this often gives even more power to the idea of satan. However, if God is at war with Satan, many people wouldn't like the idea that he is at war with part of ourselves. Or that we war with ourselves. Yet we do. Perhaps the spiritual struggle is very much internal...
Anyway, this is just a summary of many perspectives on Lucifer, Satan, and the Devil. And as I said in a response to a comment on my Friday post, these facts about the development of the theology of Satan do not negate the possibility of Satan as a fallen, sentient angel. We just need to remember that it doesn't come from the Bible.
For more reading on this material, I highly recommend Elaine Pagel's lecture, The Origin of Satan in Christian Tradition. The wikipedia articles on Christian Teaching About the Devil, Satan, Lucifer, and War in Heaven are also pretty good summaries of the differing viewpoints.