Vampire Diaries. It has more action and conflict rather than twilight, which is mostly just love. I cant say for the books, because I tried reading the vampire diaries after id seen the show, and it just made no sense to me so i gave up :P
Well if you are refering to the books i would say that Twilight is definately better than the Vampire dairies. But if you are talking about the movies... well i don't know. VD is a amazing. But i like Twilight too. So i don't know. Maybe Twilight.
I love them both I really do but The Vampire Diaries I absolutely cannot get enough of. You wait a whole year to see a Twilight film and you leave thinking ahh yeah that was everything I wanted it to be, I'm satisfied for another WHOLE year. But The Vampire Diaries I think like this but on a weekly basis! I literally can't wait until the following week because they pack so much into one episode it's like getting a weekly film. Twilight I love you but TVD I CHOOSE YOU!