Certainly, putting Dracula in any TV show or movie that has the word "vampire" in its title or even just vampires in its cast is like having John Wayne or Clint Eastwood in any kind of western. Dracula and vampire are synonymous in most people's minds, so having him make an appearance on "Buffy" in any capacity, much less the big bad of the week, was supposed to be a really big deal. Unfortunately, the actor cast in the part and the way that the character was portrayed didn't conform to what is considered the "real" vampire, so the episode kind of fizzled. That's always been kind of sad to me, because I'm probably one of only 6 people on the planet who actually LIKED the way that Dracula was portrayed, mainly because it WAS different from what we saw with Lugosi, Lee, or any of the more modern versions. He was well dressed and seemed to be, in his own special way, sophisticated and, to me at least, less of a real monster than his "reel" image had ever portrayed before.
But the thing that made him special to me is mostly that he didn't conform to what vampires in the Buffyverse were supposed to be. He could change forms, didn't lump out when he attacked anyone, and stakes obviously hurt, but didn't do him any permanent damage. We never saw him in the sunlight, but I think that it was mentioned or at least implied somewhere that Direct sunlight wasn't fatal to him, either. He was the Superman of vampires, just like the first ubervamp in Season 7 was the Incredible Hulk of ubervamps.
(Incidentally, did anyone else notice that, in his appearance in Season 8, he DID go into normal vampire game face when he changed? And that was before the Gypsy spell was nullified. Faux pas on the part of the writers, or could he actually control whether or not his features changed?)