Originally Answered: Is there a series similar to Twilight?
Some of these aren't a series, but if you have read Twilight, you should read these too. Some of these are classics. Depending on how fast you read, they might or might not take you a while to read/finish. Give 'em a chance!
All of L.J. Smith's Novels:
http://www.ljanesmith.net/booklist.php (I especially recommend the NightWorld, the Vampires Diaries, and Secret Circle series. You got vampires, witches, dragons, romance, Wild Powers, action, etc. AND, the CW is making a show based on TVDs for the Fall lineup: http://www.vampire-diaries.net/ (has everything you need to know.))
Vampire Academy series by Richelle Mead
http://www.amazon.com/gp/series/93423/re... (I have only read the first one, but I REALLY liked it. Romance, action; fast paced, great all around. I can't wait to get my hands on the rest(I hear great things)--I think its my second favorite series after L.J. Smith's NightWorld series. And, I've heard the new one is awesome!)
Sunshine by Robin McKinley
http://www.amazon.com/Sunshine-Robin-McK… (This is...different. Certainly mature. It took me a while to finish, but it has grown on me. The author has an interesting writing style, and the take on the world is new. Actually, the writing style reminds me a little bit of Ann Rice's, with a splash of humor and a little romance--a bit of a love triangle actually).
The Queen of the Damned by Anne Rice
http://www.amazon.com/Queen-Damned-Vampi… (You should read the first two? in this series but you don't need to (I haven't). Enough of the details from those books are given for you to understand this one, and it doesn't continue the first two, its connected sure, but it's its own story. The title says it all. The Queen. She falls in love. She destroys, people react, people fight, and it's a bit mordid. Hell, the Queen is spooky as hell. From my research, there are ten books in this series.)
The Historian by Elizabeth Kostova
http://www.amazon.com/Historian-Elizabet… (Mixes history and travel with old fashioned vampire lore, undertones of romance, and has an interesting way of going about it. It's a rather large book so does get a little boring in parts, but the author is very good with her details, and the story will draw you in.)
Christine Feehan's 'Dark' Series:
http://www.amazon.com/gp/series/92929/re… (These are good. The concept is different than your average vampire/love--though take a little bit of Anne Rice and mix in some NightWorld LJS soulmate concept--but they are mature, very. Not nearly as bad as LKH's later Anita Blake books, though).
Anita Blake series by Laurell K. Hamilton
http://www.amazon.com/gp/series/118?ref%… (I have to recommend the first nine novels of LKH's Anita Blake series--there's really cool plot ideas, vampires, shapeshifters, a love triangle, etc. Anything beyond the 9th book is up to you--I've read up to the 10th book--I liked the 10th book--but I stopped after that because that is one where things get...dicey, and it gets much more sexual after that one. A lot of people stopped reading them after the 10th book because of the sex/bad writing, which is why I only recommend the first nine.)
The Silver Kiss by Annette Curtis Klause
http://www.amazon.com/Silver-Kiss-Annett… (Murder mystery, sweet love story between a vampire and a young girl, not your average ending, even a little sad, but worth it.)
Companions of the Night by Vivian Vande Velde
http://www.amazon.com/Companions-Night-V… (If I remember right, this was one of the first vampire novels I ever read. It's got a little bit of everything: murder, vampires, love interest, kidnapping, etc. It's a quick read, but good. I still go back and reread it often, and I'm much older now.)
Happy Reading! :)