I play a conjurer.
I'm going full health, so i would enchant it with +magicka and, as i am a breton, with magic resistance because npc mages are really brutal.
reduce destruction 50% and reduce illusion/alteration/conjuration 50%.
Because seriously, mages are unplayable without those reductions. Alternatively, a ton of +xx magicka enchants so you don't have to inject mana potions in your veins every two seconds.
Well...i summon my atronarch, my bound sword and then i don't need magicka until my sword disappears (very cheap magicka-wise) or my atronarch dies (fire atronarchs are cheap, other atronarchs are tough).