Which minions should I use for Other specs though, both for leveling and Dungeons/raiding?
Which Warlock minion to use for when?
For dungeons and raids, Affliction is going to use the Felhunter the vast majority of the time. Demo is going to flip between the Felhunter for single targets and Fel Guard for AoE targets.
I highly recommend checking out the various spec threads on Elitist Jerks.
Affliction: Felhunter 24/7. The only exception is to bring out the Succubus if the target you are attacking is out of melee range, or when fighting against a melee class in PvP, for the Seduction outweighs the silence against something like a warrior or rogue.
Demonology: 3+ targets close together, Felguard. Single target, Felhunter. Also demo locks picked up summoning a felguard, popping Demon Soul+Trinket+Meta+Doomguard and such, with a Soul Burn: Summon Felhunter lined up to maximize single-target DPS on boss targets where you have the chance to do so. Mainly because the Felguard Demon Soul affecting all damage plus adding spell haste totally tears apart the Felhunter's bonus damage to BoD and Corruption.
And with Guardians it's plainly obvious, Infernal for AoE, Doomguard for single-target.
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