First off, I don't consider either The Sword or High on Fire Doom. the sword is close I suppose. same with Down, they are not doom, but they're fucking awesome...
want some real stoner doom check out, Spiritual Beggars. some sweet classic Doom would be Cathedral, Pentagram, Krux, Candlemass, Memento Mori.
want some Doom Death (Daylight dies is doom death fyi)
check out. Swallow the Sun (by far the best doom band out there)
Novembers Doom, Saturnus, Early katatonia (brave murder day) Early Paradise Lost (new PL is awesome but more gothic rock than doom.) My Dying Bride is a good mix of Doom Death and Classic Doom... Slumber is recomended for everyone as well, the album Fallout is almost perfect 9/10
I also Highly recommend Draconian, Doom Death with Beauty and the Beast vocals (growls mixed with a chick singer)
some really meloncoly clean vocal doom is The Foreshadowing (amazing debut album)
Rapture is very good doom mixed with Melodic Death metal.
if you like some of those bands also look into... The Old Dead Tree, Novembre, Moonspell (some stuff is Doomdeath), Godsend
also anyone that likes daylight dies should enjoy Insomnium... they have doomish lyrics but the instruments are melodic death, they are IMO the 2nd best melodic death metal band out there... number one is Dark Tranquillity
Opeth is in a class of their own