When I first heard about The Vampire Diaries, I expected it to be just like any other teen drama, and decided to watch just because I wanted to see how bad it really was. It completely changed the expectations I had in mind, and I was hooked. I watched the first season in a week, and caught up with the rest pretty quickly. Overall, the plot is good, there aren't many continuity errors, and the acting is surprisingly pleasant.
One of the only things that bug me about the show is Paul Wesley's (Stefan) awful, cringe-worthy acting. He always has the same "brooding" face and never changes expression. This was even successfully lampshaded
Another thing that's bothers me is that sometimes they drag out some storylines for too long.
Overall, it is a show worth watching.