I just happened to see this thread, I didn't see that it 100+ replies (and could never read so many) but I just wanted to put my 2 cents in (even though someone has probably already said this).
IMO Lucifer is not part of real Christianity. He is never mentioned in the Bible (nor is the 'Devil'). Only Satan is in the Bible, and I was always taught and firmly believe from the text, the sources, Jewish tradition, and logic, that the Biblical 'Satan' (just like the serpent) is an 'allegory' for human temptation, and was never meant to be, thought to be, nor was intended to be believed as a real 'being'.
Allegory (representing something spiritual or emotional as a material being) was done a lot in ancient times just like in later day literature and stage plays. Greed, lust, jealousy were all represented by actual characters in plays and stories to make them more 'real' for the audiance. No one expected that anyone would actually think 'greed' for example actually exists as a 'being' instead of being a human emotion. No one really thinks jealousy is a 'real' 'green eyed woman'. Even primitive people knew serpents couldn't talk and that the snake was just a 'representation' for Eve's temptation to disobey. Satan throughout the Bible is just a physical 'stand in' for human 'temptation to do wrong'. He's supposed to be the little voice in your own head that tempts you to do something you know is wrong.
As far as Lucifer...he was created as an imaginary fictional character in the 1st century BC Jewish popular literature 'The Book of Enoch' and 'The Life of Adam and Eve'. These were fictional books for the wealthy and often literate Greek influenced Jewish public of the time 100BC-0AD with religious themes (think of today's 'Da Vinci Code'). That's where all the fallen angels, Lucifer etc. etc. comes from, not from the Bible and not from Christianity.
The Persian 'devil' (horns, trident etc.) was simply picked up by later Romans and is a pagan myth, not Christian or Jewish.
In the 4th and 5th centuries AD (400's/ 500's AD) new Roman upper class converts to Christianity (who were scholars and writers) like Augustine of Hippo mixed these things in with Christianity because they didn't know Christianity very well. Then right after, the 'Dark Ages' happened 600AD-1000AD and it stuck.
Lucifer is never mentioned in any part of the Bible....In Isaiah 14 3-20 Isaiah mocks the King of Babylon by using the kings self given grandiose titles....morning star, son of the dawn, king of the world etc.....The word 'lucifer' in Latin 500 years later happened to mean 'light bearer or morning star' but that has nothing to do with anything and is just coincidental to anything Isaiah meant (Isaiah being way before Rome existed and not speaking Latin).