Favorite school: Destruction
Favorite spells: Fire Storm, Lightning Storm, Frost Storm *cough* I meant Blizzard
School I can't go without: Enchanting. Enchanting is always "on" and doesn't require consumables. I admit it would probably be really irritating if I couldn't remove the old enchants when I want to bolster them, but that's what mods are for.
Comments on other schools:
Conjuration: I keep trying to like it. So many people love this one. But I am sorry, I love the awesome variety of melee kill cams, and summoning minions to kill things takes that away from me. Also, after fire atronach they are all a bit ugly.
Restoration: Nice, but feels lack luster. Needs some anti-demon spells added (not just anti-undead)
Alteration: Normally I don't care for this, but recently found out that with max Alteration & SPERG mod, it frees me from being stuck with an armor type. I can use whatever, however, whenever, and have the same mitigation (80%). That is just plain awesome as it reduces me from wanting to reroll to wear some awesome new armor type that I didn't spec for.
Illusion: Either really frustrating (enemy resists...etc) or way overpowered. Nice synergy with sneaky types, but don't bring a companion or they run in and aggro anyways. Gah! I also avoid invisibility like the plague.