iMtG Server: Gathering

Max Vampire 75 cards, 15 sideboard 1 {Bojuka Bog} 23 {Swamp} 24 lands 2 {Nirkana Revenant} 2 {Bloodlord of Vaasgoth} 4 {Vampire Nocturnus} 2 {Bloodline Keeper} 3 {Captivating Vampire} 4 {Vampire Nighthawk} 2 {Kalastria Highborn} 3 {Bloodghast} 4 {Guul Draz Assassin} 26 creatures 4 {Feast of Blood} 2 {Sorin Markov} 2 {Liliana of the Dark Realms} 2 {Liliana of the Veil} 10 other spells Sideboard 4 {Hero's Downfall} 3 {Victim of Night} 4 {Doom Blade} 4 {Deathmark} 15 sideboard cards

Love the list, but would try -2 nocturnus for +2 bloodline keeper.
The keepers boost once transformed and get more vamps on the field for you and for te captivating vamp.
Whilst the nocturnus is awesome, you're revealing your next draw and the bonus disappears when you hit land, which makes it a little less consistent the the keeper IMHO.