I'll take the same approach as Serio. The ones I have not beaten:
Vampire Killer for MSX(I don't have it)
Haunted Castle(I don't have it/Haven't seen it in any arcades)
Vs. Castlevania(Same reason as Haunted Castle)
Castlevania: Dracula X(SNES, I don't have it)
Legends(I don't have it)
Bloodlines(I don't have it)
Castlevania 64(I don't have it)
So, basicaly, the only games I haven't beaten are the ones I don't have.
Oh, wait, I forgot all the nutzo Commodore/Amiga/PC ports of CV1, but I also don't have them.