My Latin teacher's favorite phrase for us to translate was "There's nothing new under the sun." (My Latin teacher was notoriously slack—he'd often give us the same phrases on tests—sometimes he'd even give us the same tests over again because he didn't feel like making new ones. Anyway, it got so that if I saw a line that contained "sol," I knew it was the above phrase. I didn't learn any Latin, but I did make an A.)
My point is, we're all just repeating stories (usually; there are some awesome completely unique stories...but I digress. Again.). The bildungsroman, the hero's journey, Cinderella, Beauty and the Beast...there are variations of these stories everywhere. And it's not a bad thing: one of my favorite movies is Ever After...to say nothing of Star Wars (which would be the entire reason I wore long hair in braids for most of my life).
The key, I think, is to make a unique variation of the story. Even straight up re-interpretations of old stories—much of Shannon Hale's works, or even Percy Jackson—puts a new twist on the story to keep it fresh.
I hope that, when you read the synopsis I've posted before, you can't tell the Greek myth that inspired it. I really hope not. But what if I told you that the main character's name is Belle Ravenna? Or that one of the key things in alchemy they learn is the concept of solve et coagula (ha! I did learn some Latin! It means: separate and join together)—and that the alchemists "separate" different animals to "join together" new ones—like separating an eagle and a horse to make a pegasus?
Hmm...I think I'll be cruel and let you all think about it for a bit. You'll find out in a day or two (as long as Blogger's posting these things right!).