What a great question!
Interestingly, with the significant exception of Barnabas, I have never really been a fan of vampire lore. However, I have always loved ghost stories and mysteries of various kinds.
I must have seen only about a year or so of DS when it originally aired and I always looked forward to seeing it with Mom, who would first watch GH with me, too.
More than 30 years passed until I rediscovered DS a couple of year ago, largely thanks to GingerCat's recommendation.
As I recalled very little of DS intricate plots from its initial airing, little less was remembered than Barnabas, Julia, Angelique with her evil laugh and that wonderful, eerie score.
Yes, I would have to say the music, Barnabas, Angelique and Julia, about in that order, were the elements that brought me back - quite unexpectedly - to the ranks of DS fandom. Oh, and I must also mention the delicious Quentin, whom I never even had the pleasure of seeing the first time round!