I'm calling the Final Fifth:
The producers of BSG have said that the final fifth cylon will not be a character that has been central to the show. So before this, we were strongly considering Baltar, perhaps Roslin, adn ow more recently with the singing Gaeta. However, we have to remember one event in particular. Season 3 Episode 8. In this episode we learn that Bill Adama is responsible for starting the cylon war. We also come to learn of a rather insignificant character seems to be created for a filler episode - Bulldog. Bulldog, who conveniently escapes from a baseship and has raiders on him that miss firing on him (Hmm . . . where else have I seen a Cylon miss or not shoot at point blank range? Season 4 opener perhaps?). Furthermore, when we remember that Diana apologizes says "I'm sorry . . . I had not idea" we believe she might be apologizing to Baltar who she had recently tortured, but it may in fact be Bulldog, whom she toyed with the most.

The Unknown Sixth
Also, going on the whole definition of revelations and apocalypse. (See Wiki: http://en.wikipedia.org/wiki/Apocalypse). We see that something will be revealed to human and Cylon. Furthermore, we can then introduce the idea of the antichrist.
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"Beast" - Endtime Ruler; also known as Antichrist
In the Old and New Testaments, a particular individual is singled out as the particular focus of God's wrath. This individual is known in biblical scripture by many titles such as the "beast", the "little horn"[17][18], the "prince that will come" and other titles. One ancient prince was singled out in scripture, the Prince of Tyrus, who may be considered a 'type' of antichrist. [19]

After the judgment of the Prince of Tyrus, God directs the prophet Ezekiel to write a judgment about the King of Tyrus, and from the scripture is learned that this individual is not a human being, but "the anointed cherub that covereth". [20] From further reading of the text it is learned that the cherub being addressed here is Lucifer (or Satan), as this was his former position before the throne of God before his fall. Satan is also viewed as a 'prince'[21] [22][23] that will eventually be judged.

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This points to Baltar. So who do you know that the Cylon God has machinations, can apparently "project" like other seraphim/cherubs (cylons), and essentially can do whatever he wants in the fleet?

Furthermore, in the Opera House, we see that there are 6 banners, when for the FInal 5. I used to think this banner was reserved Hera ("The First of God's new generation") but since there are two such children Atehna's and Tyrol's child (a proverbial Adam and Eve, of course that's if Cali didn't cheat), there should be seven banners. Instead, since Baltar has a hand in all of this, acting as the neccessary evil left hand of God, we can give Baltar this special honour.

One more thing!!! The Six Delusion and Baltar Delusion both appear To Gauis. The Baltar Delusion is also known to appear to Caprica Six. Furthermore, Hera starts drawing about Caprica Six, an allusion to the Opera House and the next step that is coming where Hera is the child of Both Baltar and Six Delusion (Angel of God/God). Six. Six. Six. Although there are a Final Five set of cylon, we can see that the sixth banner points to Baltar.

Other questions for considerations:
On a seperate note, if Hera is the next of God's new generation, then what about Tyroll's son. He hasn't really been given any significance, and I don't even think I know his name. What is the role of "God's new generation" when considering the theory that "humans", the Final 5, and the Significant 7 are all humanoid AIs based on the originals humans of earth?

Like other Scifi, Ghost in the Shell, the Matrix, Neuromancer (River Styx oddly familiar to beach seen), we see this idea of "1 is not enough, 2 is too many." Meaning, there is a fusion between man and machine to make a new life. And it is this new life that is endeared with evolution. In all these films, we see that machine based beings cannot reproduce sexually and are copies, therefore they cannot evolve, BUT we also see humans are struggling with the limitations of their being are willing to go to some measures to "beat the meat." As a result, both consciousness tend to meld, and are able to gain a more holistic insight into the universe.

So, in order to keep this scifi/cyborg themes consistent, then the "new generation of God's children" represent something fundamentally different and new. And therefore, if everyone is some kind of cylon, or an advanced cylon breeding with an F5 or inferior S7 cylon, then the the "new generation" is not new or novel at all, nor holds new evolutionary relevance. They're an evolutionary dead end, or unintended accidents. But given their significance, which has been building since season 1 episode 3, to the end of season 1, through 2, unto the Opera House scene in Season 3, there must be some other reason attached to their existance and creation. And I believe discovering this holds the key to understanding what the FRAK is going on in the BSG universe.