1) Darkest Powers Series by Kelley Armstrong (Book 1- The Summoning)- The first two are The Summoning and The Awakening. The third book in the trilogy is The Reckoning, due out May 2010. You can read about it
2) The Chronicles of Vladimir Tod by Heather Brewer (Book 1- Eighth Grade Bites)- The first two are Eighth Grade Bites and Nineth Grade Slays. The series has an interesting premise, lots of books have vampires going through high school, but in this he is going through all of this for the first time. So in addition to dealing with puberty and school, he has to deal with being a vampire (and must remember not to bite his friends). You can read more about it here.
3) The Morganville Vampire Series by Rachel Caine (Book 1- Glass Houses). The first two are Glass Houses and The Dead Girls Dance. You can read more about them here.
4) The House of Night Series by P.C. Cast & Kristin Cast-(Book 1- Marked) The first two books are Marked and Betrayed. You can read more about it here.
5) The Mortal Instruments Series by Cassandra Clare (Book 1- City of Bones). The first two books are City of Bones and City of Ashes. You can read more about it here.
6) Wicked Lovely Series by Melissa Marr- the first two books in the series are Wicked Lovely and Ink Exchange. Click here for the author's website.
7) The Vampire Academy Series by Richelle Mead- the first two in this series are Vampire Academy and Frostbite, followed by Shadow Kiss and Blood Promise. Click here for the author's website.
8) The Immortals by Alyson Noel- the first two in the series are Evermore and Blue Moon. Click here for the author's website.
10) Vampire Kisses by Ellen Schreiber- the first two are The Beginning and Kissing Coffins.
11) The Night World Series by L.J. Smith- the first nine have been packaged into three volumes. The first volume includes Secret Vampire, Daughters of Darkness, and Spellbinder. You can go here for the author's website
12) The Vampire Diaries is another series by L.J. Smith, and has also been turned into a TV series. I've only seen the first episode but it looked promising (I'm not a regular tv watcher- my schedule is not very regular and I never remember when things are on, so don't judge it by me).
13) Blue is for Nightmares Series- the first two are Blue is for Nightmares and White is for Magic. The fifth is actually a graphic novel titled Black is for Beginnings. The author's website is here.
So. What's on your list? :)