I'm posting that here because based on the books, how much is The Secret Circle like The Vampire Diaries in terms of being Twilight-ish, having historical elements, having interesting adult characters, having a complex plot that keeps building, etc? It it basically TVD with witches, or does it have a distinct quality?
*Warning: spoilers for TSC and TVD books ahead. Not spoiler-tagging because they've been out for over a decade, and because it should be obvious that answering this question requires spoiling the books.*
As someone who's only read the books, I can say that The Secret Circle books have a bit of the historical element, actually more than the book Vampire Diaries do (from what I've gleaned through online osmosis, I understand that the TV TVD made Stefan and Damon Civil War-era humans, not 15th century Italians.) The Secret Circle books contain the occasional flashback/vision to a 17th century timeframe, and the antagonist is actually a witch from that time frame who managed to make himself immortal via use of a crystal skull and some magic.
I like the Secret Circle books a lot better than the Vampire Diaries ones. All of LJ Smith's books are fairly similar (heck, some of the character tropes get re-used between her series) but I found the characters of TSC to be more likeable overall. Neither of the book series features many adult characters, and in TSC most of the people who would figure to be adult characters are dead (half of the titular Circle's parents died trying to stand up to the antagonist, while the other half were too cowardly to go.) I suppose the TV show could get some interesting material from the surviving parents, and there are a few older relations who are interesting (Cassie's grandmother being the main one.) Another big spoiler, which I don't know if the Secret Circle TV show people will do: in the books, there's the whole "Luke, I am your father" twist with Cassie and the antagonist.
I know they'll have to have cut a bunch of characters, but in the books, the coven was composed of 12 witch families who'd married and interbred since Salem witch trial times (somehow without incest, but I chalk that up to the author being not very good with genealogy.) The families were part of a small town called New Salem, and there's a lot of tension between the witchy families and ordinary people. So the writers could get a lot of small-town-dynamic out of that.
As for slowly building plot with multiple elements, they're about the same. There's definitely the teen romance stuff, but it's less Twilight-ish than TVD. (FWIW, I enjoyed these books a LOT more than Stephenie Meyer's, but there's a certain amount of nostalgia - I found TVD/TSC when I was in middle school and therefore target age for this stuff.)
Also, I saw the same news note (on Hypable) about how, although TVD and TSC could be set in the same universe, but at the moment the creators don't plan on any crossovers or actually having them set in the same universe. Based on the source material, I think the writers could get a lot of mileage out of TSC, moreso than I would've thought for TVD.
Britt. 
