I am currently in the process of writing my first full length film, i also Direct and shoot all my films, It is a modern twist on a vampire love story, and i want to make the lair for the vampire, but im not sure how to go about it, Can i get some idea's on what would be good vampire Decore?

Might depend on how much you are able to spend.
My advice would be to watch as many old horror films as you can get your hands on. I'm talking one's from the 30's and 40's (eg. Bela Lugosi, etc). Study these films for their art direction and production design, and see what you can incorporate into your own film.