Effect Negation: These decks have Dark Ruler Ha Des and Wicked-Breaking Flamberge - Baou in them. They could have a Skill Drain or two. These decks are mainly geared toward surrounding your opponent and beating them in the face.
Dark Necrofear: These decks vary and, though they may have Dark Ruler Ha Des, they typically dont need Wicked-Breaking Flamberge - Baou or Skill Drain. They are also surround decks but more by special summoning.
Archfiend: Well... archfiend decks... Terrorking, Infernalqueen, so on... Surround and Invincibility are their strong suites... with their "you cant attack or target my monster" sorta deal.
I vote Effect negation.
I would have to say Archfiends...they are so EEEVIL!!! >:( >:( >:(
I say Necrofear, because it doesnt exactly have to rely only on Necro, it can have ANY fiend FOR Necro food.