Fred Saberhagen's Dracula books:
_The Dracula Tape_
_The Holmes-Dracula File_
_Thorn_
&c.
There's a lot of other contemporary vampire fiction, but really, nothing worth else more than mere entertainment if that.
I second Caleb's suggestion of Susan Cooper (and some members of The Dark are rather vampire-like).
He might enjoy the H.P. Lovecraft stories which are in many ways the under-pinnings of modern horror.
Lastly, a book which I think every teen-ager (boy or girl) should read, Hal Gordon's _Divers Down! Adventure Under Hawaiian Seas_ --- oddly while not available as an ebook (AFAICT) it is freely available as an MP3 --- highly recommended for any holiday travelling:
http://www.sffaudio.com/?p=6202
feed://www.uvulaaudio.com/kids/Kids.xml
(first link is an announcement w/ link to first .mp3, second is long list of many links incl. all 8 parts of Divers Down!)
William