LOL, I love all the conflicting stories so far on this, so I'm just going to add another one.
This is how it went down:
God created his angels first, and among all of his angels he created the infamous arch-angels, who were to rule over all other angels and be given more power and so on. Out of those arch-angels, god decided he wanted to have a sort of "equal", where as all of the other angels he created including the arch-angels didn't have the knowledge of the universe as god did. So he chose Lucifer to be the supreme angel, and nearly gods equal in power, wisdom and knowledge. God laid out his plan and created the universe, much the same way as we understand it was created in science (big bang) setting everything in motion from the beginning of time, the heaven's and the earth and explained to his angels how things were going to work. Obviously for a long time angels had nothing much to do, they watched the passage of time over the eon's, playing with algy, microbes, and eventually dinosaurs. Wondering when the earth would be ripe for these so called "humans".
Humans would be created in Gods image and be given all the choices that god had. If humans were evil, they would not ascend to God's realm aka heaven. Of all his angels, only Lucifer would question the things god did, and so Lucifer wondered how human's would know right from wrong. God said that humans would know in their heart of hearts and all his angels took his word for it including Lucifer. At this time, however, Hell did not exist - there was only Heaven and purgatory. All humans would die and then their souls would travel to purgatory, if they lived a good life would ascend to heaven - but if they didn't, their souls would remain in purgatory.
Well, at first of course humans were rather peaceful creatures, most if not all of them would ascend to heaven from purgatory. Until pandora's box was opened and all the sin, hate and wickedness was dispursed to humankind. After this happened, only Lucifer and God were concerned. Its not really known for sure, but assumed that all of the other angels were merely incapable of questioning God or his will. God said that humans should be left alone, to their own vices and the pure of heart would still make it.
Well thats not what happened, more and more souls were living out the rest of existance in purgatory. Lucifer became concerned with this and wondered why god wasn't more concerned as he was. Lucifer would watch from heaven and ask god constantly about different circumstances surrounding why those souls were so confused. At this time, God's other arch angels were also growing concerned. They were still incapable of questioning god's will, but also understood where Lucifer was coming from. With a few spoken hints that other angels within gods ranks were also concerned that maybe god wasn't doing this right, God eventually sat down and asked his arch angels what they had in mind. They eventually talked God into allowing him (Lucifer) and other arch-angels to visit humans on earth and try to influence their ways, but God gave them limits because he still had it in his mind that humans should have every thing god had, which included the choices all of us make everyday.
Things still didn't change much, and Lucifer eventually talked god into going to earth and seeing his creation first hand. God decided he would issue the 10 commandments, and this way humans would know exactly how to live their life and how to ascend to heaven. Well, of course humans still had the choice and many chose not to follow them. More and more souls crowded purgatory, trapped for all eternity. This situation became more and more disconcerting to Lucifer (and rightly so) until he eventually just flat out told god he thought he was doing things wrong.
"Well what else would you have me do, Lucifer my son" god said, "I've instructed them to the letter". Well Lucifer gave the age old argument, "how do those being know of your existance father, for all they know those commandments are hog wash." These discussions eventually led God to consider Lucifer's plan. To go to earth and show humans he existed. But god would not do it directly, he would go as a human (Jesus) and die for anyone who would except him as their god. Things played out pretty much how Mel Gibson said they did in "Passion of the Christ" and God died for his beloved humans.
Well Lucifer didn't like this, but excepted it. "Humans have to have faith in me, showing them my existance out right is simply too easy." Lucifer decided that since he got something out of his discussions with god, to argue about it no further. Except that after God died for our sins, purgatory would still fill faster then ever. Lucifer decided new action needed to be taken. Clearly humans needed more guidance, and if God wasn't willing to do anything more then Lucifer would take it into his own hands. Lucifer would spend nearly all of his time in purgatory, talking with these lost souls. Most of the new arrivals hadn't heard Chirst's word, and didn't know that their god (usually Zues) was no longer the god and was thus, not admitted. Lucifer realized what was wrong with this picture, God had given his blood to wash our sins and allow us to heaven even if we had sinned. But only if we believed in him. So instead of solving the old problem, he merely created a new one.
Well Lucifer spent more and more time there, finding the souls he deamed worthy of heaven. And then using his own power to usher them into heaven's pearly gates. Lucifer only chose souls that were pure, but hadn't heard Christ's word - this way God would probably not find out that more souls were being allowed into heaven these days. What was the chaos of billions of souls in purgatory, suddently became a much smaller accumulation. Eventually God caught wind of what Lucifer was doing, and confronted him.
God wanted Lucifer to be punished and was so infuriated that he couldn't even think of an appropriate punishment. However, something unexpected happened. All of gods other arch angels began to speak up for Lucifer. They felt that he had been doing the right thing. They wouldn't tell god that he was wrong (although this is what they believed) but that Lucifer shouldn't be punished and that god should forgive him. Eventually god told Lucifer that he had a choice, he would be stripped of all his arch angel powers - this was non negotiable. Lucifer could live out his days in heaven, with none of the freedom's he previously had, or he could be given some of his power back - and given reign over a new realm. That of purgatory itself. God would allow Lucifer to try and teach these souls the ways, and any who truly excepted god and eventually served there time (time served depends on sins committed in life) would be allowed into heaven. Lucifer was very happy, this is what he had wanted all along.
So you see - Lucifer isn't the bad guy, in fact he's just the opposite. He eventually saves the souls of people like me who don't believe in god, but don't really sin in life. Lucifer is the aetheist's/agnostic/jewish/muslim/buddist/etc. savior. Since as we all know only Christians are going to heaven. God had forsaken people like us, people like me and like you (talking to the jews).
Thanks for reading my story
cliffs:
god created his angels
god named one angel his equal, lucifer
god created man
god commanded man (10 commandments)
god died for man (christ's crucifiction)
god still allowed souls that didn't go to heaven, to rot in purgatory
lucifer defied god and let some departed souls in any way
god got pissed
angels stuck up for lucifer
god had no choice but to allow lucifer the ability to guide the misguided humans to someday reach heaven
lucifer became commander of purgatory
christians later renamed purgatory hell in order to make people behave and labled lucifer as the "bad guy" and gave him a new name, and new look (satan and goat being instead of beautiful angl)
moral:
lucifer is actually the good guy, he is the one looking out for 3/4 of the earths population. God only cares about the Christians