Pre-dating Twilight by about 10 years, Vampire Diaries may seem similar but it is a fair bit darker. It's a story about a love triangle between two vampire brothers (one trying to be good (Stefan), the other all about the evil (Damon)) and high school hottie - Elena. Add the standard teen backstabing and a bit of occult and you've got the basics. The first two books in the series - The Awakening and The Struggle follows our heroine as she falls in love with the good brother and be tempted by the evil one.It isn't as dramatic a tale at first as Twilight but stick with it and it rapidly becomes addictive. The big difference is the darkenss of the stories - much more horror with murder, greeping mists and scary birds. Even the good vampire isn't as good as the Cullen family.
If you've seen the TV show and enjoyed it then you should read the books. Although similar in many key ways they are both very different. Not least that the brothers were turned into Vampires during the Italian Renaissance not the American Civil War (making the age gap between the teenage girl and the vampire about 400 years). This dramatic time gap means many of the key points in the books don't exisit in the TV show for example Katherine, the vampire that turned them, features in both but her influence and back story is very different.
If you want to read more about ther series then try the offical book site or one of the many fan sites.
