The TLDR version of this is that Harry Dresden is the Second Coming of Jesus Christ. This is beyond a tinfoil hat theory - I'm now wearing a tinfoil suit, with my office located in a tin mine somewhere. But the evidence seems to keep piling up to me, so read on if you find the speculation interesting.

We learned in Peace Talks that a Starborn is a cycle that occurs every 666 years.

It's the first connection we've had  linking Biblical lore to the Starborn status. It made me wonder if  Jesus qualified as "Starborn". The Bible certainly has the whole Born  under a Star / 3 Magi bit in it. If you run the math, the timeframe is  off by +/- 15 years, which cratered my speculation at that point.
But...I keep running into narrative clues.

For instance this little tidbit from Storm Front:

The  world is getting weirder. Darker every single day. Things are spinning  around faster and faster, and threatening to go completely awry. Falcons and falconers. The center cannot hold.
But  in my corner of the country, I’m trying to nail things down. I  don’t want to live in Victor’s jungle, even if it did eventually devour  him. I don’t want to live in a world where the strong rule and the weak  cower. I’d rather make a place where things are a little quieter. Where  trolls stay the hell under their bridges and where elves don’t come  swooping out to snatch children from their cradles. Where vampires  respect the limits, and where the faeries mind their p’sand q’s.

My name is Harry Blackstone Copperfield Dresden. Conjure by it at your own risk. When things get strange, when what goes bump in the night flicks on the lights, when no one else can help you, give me a call. I’m in the book.

Falcons and Falconers. The Center cannot hold. Both of those are references to a  poem by William Butler Yeats. The name of the poem?

The Second Coming

That little warning at the end of Storm Front? The book that he's referring to? It's not the phone book...it's the Bible. The warning about conjuring by his name....you don't conjure by a name of God idly.

Here's some more textual foreshadowing, if you interpret it in a certain light:

Fool Moon

Denton stared at me as the soul gaze broke and we were released. He wasn’t reacting well to whatever it was he had seen inside of me.  His face had gone white, and his hand was trembling, the barrel of the  gun wavering every which way. He lifted his other hand to mop beads of  cold sweat away from his face.“No,”  Denton said, white showing all around the grey irises of his eyes.“No,  wizard.” He raised his gun. “I don’t believe in hell. I won’t let you.”

 

Summer Knight

“Harry  Dresden,” he said dryly, “Meet Martha Liberty.” She shot him a look and  said pointedly, “He’s arrogant, Ebenezar. Dangerous.”I snorted. “That’s every wizard ever.” Martha continued as if I hadn’t spoken. “Bitter.  Angry. Obsessive.” Ebenezar frowned. “Seems to me he has good reason to  be. You and the rest of the Senior Council saw to that.”Martha shook her  head. “You know what he was meant to be. He’s too great a risk.”

Changes

I exhaled wearily, and stopped even trying to hold the spell. “I don’t understand.” Uriel nodded. “That’s the difficult part of being mortal. Of having choice. Much is hidden from you.” He sighed. Love your child, Dresden. Everything else flows from there. A wise man said that,” Uriel said.

Cold Days

“And  on a similar note, do not underestimate yourself. You haven’t been  given the power and the knowledge and the allies and the resources you  possess for no reason, Harry. Nothing I have to say can possibly make  this task any easier for you. The only way to do it is to do it. He  lifted his chin. You don’t need help, Warden. You are the help.”

Peace Talks

Their  thoughts, or whatever madness it was that passed for them, began to  devour mine. I felt like my mind was being chewed apart by a swarm of  ants. And then for just an instant, the alien thought patterns made  sense, and I saw an image from their point of view – a  being made of coherent light, a column of glowing energy centers, and  pure dread, standing like an obelisk before the cornerhounds, a bolt of  terrible lightning gathered around its upraised fists, head, and  shoulders, like a miniature storm front.
I saw what they saw when they looked at me.
And I felt their fear.

Finally, we have the titles of the last 3 books in the series, the apocalyptic trilogy; Stars and Stones, Hell's Bells, and Empty Night.
I submit that Empty Night is a reference to a famous short story by Arthur C. Clarke. In the story the stars start winking out, one by one. The name of the story? The Nine Billion Names of God.

I'm  starting to strongly suspect that "Starborn" is something akin to  Jesus, an avatar of the White God. But he's all about Choice - so Harry  gets to choose to be good or evil, the same as any normal mortal  human...but the consequences of that choice could be a great deal bigger  then a normal life. Hence how everyone in the series who is in the know  are so darned nervous about him. Why more then a few keep testing his  morality. It's not on account of him being a Wizard, as he's always  thought. Morgan mentions in his microfiction about something called a Destroyer....that sounds a bit like an Antichrist to me.