I've been enjoying this series as well. Much more so than I expected. There are definitely some not-so-subtle nods to DS, most notably the Josette (or in this case Katherine) angle, which made me
as soon as I saw it. I kind of hope they do some flashbacks showing us what happened with Katherine and the 2 brothers in the past. Either in an extended DS way or in a briefer Forever Knight way. I kind of think of TVD as a sort of "DS: The High School Years" at this point, and as such I'm enjoying it. And as a classic vampire fan, I'm also happy that most of the traditional vampire myths have been kept (the "a vampire cannot enter someone's house unless they've been invited" thing, for example). And I have to say that Nina Dobrev who plays Elena (and hopefully Katherine in flashbacks) is stunningly beautiful. She's almost as lovely and enchanting as Joanna Going.
I'm looking forward to seeing where the series goes from here.