Then Between the Lines by Jodi Picoult and Samantha Van Leer
And am just beginning Cinder by Marissa Meyer which is listed as Book One in the Lunar Chronicles.
On LM_net the librarian listserv we have had a post of Young Adult must reads touted as similiar to Twilight which was compiled by a member based on posts by other librarians. Here are those recommendations from librarians all over.
Beautiful Creatures series by Cami Garcia
The Forest of Hands and Teeth by Carrie Ryan and its two sequel
Mortal Instruments series and Infernal Devises series - Cassandra Clare
Jessica's Guide to Dating on the Darkside! - Beth Fantaskey
Chicagoland Vampire series.
Blood and Chocolate by Annette Curtis Klause
Silver Kiss by Annette Curtis Klause
Shiver trilogy - Maggie Stiefvater
Gone series by Michael Grant
Dresdon series and Codex Alera by Jim Butcher
The Raven Boys Maggie Stiefvater