Let's have a look at the ominous number 666.
We know about the number 666 from the book of Revelation, the final book of the Bible.
In chapter 13, John the Revelator discusses two beasts. The first one (verses 1 to 10) comes out of the sea and seems similar to an earlier mentioned dragon who gives it its authority (v2). The second beast comes out of the earth (v11 to 18). This second beast exercises all authority of the first beast in the presence of the first beast (12). One of the acts of this second beast is to equip all people with a mark on either their right hand or on their forehead. That mark, John explains, is 666.
Is 666 the Number of the Devil?
Too bad for all the metal heads and horror fans who thought it was, but 666 is a human number, the number of a man (v 18). Some say that, surely, this "man" must be demon possessed but that too is unbiblical. In the Bible no demon ever possesses anything and at best gets to influence people. In fact, God is the sole owner of everything: the entire world (Ps 24:1), and all souls (Eze 18:4).
The number 666 is often associated with the Antichrist, but it's by no means certain that the two are the same. There are many more villains or mysterious entities mentioned in Revelation and other Bible books.
What Might 666 Mean?
John seems to invite the "wise" among us to figure out what 666 means. He says, “Here is wisdom. Let him who has understanding reckon the number of the beast” (Rev 13:18). This may seem like a summons to all smarties out there, but in the Biblical arena, understanding means something else than being smart. King Solomon says it like this, “The fear of the Lord is the beginning of knowledge” (Prov 1:7).
Wisdom starts with reverence for truth, not with being clever, and certainly not with being hexakosioihexekontahexaphobic (that's being scared of 666 - such a cool word, I had to put it in).
The Beast
The word that John uses for the creatures from the earth and the sea is "therion." Therion usually denotes ferocious creatures like lions or vipers. A verb that's tied into this word is "thera," which means to hunt or chase. Paul uses this verb in Rom 11:9 to describe a trap. He quotes Ps 69:22, which paints a picture of deception and dullness that leads to complete ruin.
It should be noted that the word "therion" did then not carry the distinct negative connotation it does today. Aspiring beast-hunters should also know that the constellation we now call Lupus was called Therion in John's time.
Suggested Interpretations
The most popular approach in interpreting the number 666 is to render numerical values to letters, transnumerate personal names and add the letter-values together (this is called Gematria). By adding titles and trying different languages, the number of the beast has been pinned to a large amount of people and institutions, from Emperor Nero to Pope Benedict and the papacy at large.
Since 666 has to do with trade, especially global trade, people have wondered if this number may have something to do with the Internet. It has been overly reported that the name Bill Gates III converted to ASCII codes would add up to 666. But a little scrutiny shows that this isn't true. The name Bill Gates in ASCII adds up to 663 but the decimal number 3 has ASCII value 51. That's 714 together.
Others note that the "w" is the transliteration of the sixth Hebrew letter (the waw), and that thus "www," the signature prefix of all website URLs, transnumerates to 666.
A similar construction (that none of the dozens of the consulted websites, including Wikipedia, mentions, so I reckon it's my claim to fame) occurs when we realize that the Hebrew word for lily is "sixie," a word which is closely related to the word for six. Displaying three lilies (Pope Simplicius, 468-483, left, and pope Paulus VI, 1963-1978, right) does therefore seem not very clever.
All this would have been very worrisome is John the Revelator had said anything about six-six-six. He doesn't. He is talking about six-hundred and sixty-six. And that is something completely different.
A More Sensible Attempt
Revelation 13 is mesmerizing but wildly guessing after its meaning has no merit. Even if we would accidentally guess right, it wouldn't serve us much if we still don't understand the meaning of the chapter, or the book, or even the Bible as a whole. Gematria certainly existed when John wrote Revelation, but nowhere in the Bible is Gematria employed or even mentioned. It is highly unlikely that John inserted a hip riddle in his book, and that the outcome of it denoted something that had nothing to do with wisdom, or even helped anyone who managed to figure it out.
We also have a saying, 'third time lucky.' Three being an acceptable amount of times to try something.
When the number 7 was used in Biblical times it meant an embodiment of perfection.(In the same way as when we say 24/7 we mean 'all the time' or when we say, 'I've told you a million times'- we mean 'totally').
NOw, 6 is the number assigned to man because in his quest to be (not like God, but as powerful as) God, he has fallen short of perfection. Not once, not twice but 3 times. Having tried his best to take on the power of God, man has failed totally. Hence 666.
This does not include humans trying to live good lives, only those who, for the love of power, have tried to be gods themselves.
Sorry for the long comment, I know you've covered a lot of this.