I like really sad and depressed doom. To me this means My Dying Bride(The Angel And The Dark River, Turn Loose The Swans), Shape Of Despair(Angels Of Distress), and especially Funerals From These Wounds. God i love that album.
Anyway, i want to mention a few things here: I dislike the overuse of acoustic parts, and half-assed emotionality(for me i dont want doom to be warm and emo, i want it to be weeping as if it was the apocalypse)
Also i sometimes dont like the "dead" feel of bands like Esoteric and Catacombs, for an example. Im just a sucker for crying melancholy when it comes to doom(though other types of doom may be alright as well, but....)