You have the hands of an illusionist: Why illusion is overpowered/fucking awesome

You may be thinking um... what? No way there's destruction for killing, restoration for healing and conjuration for getting sidekicks. The other schools are just for miscellany like 'water breathing'.

This is true. If you play a mage like you play a warrior but substitute destruction for whatever weapon. i.e. if you play a mage like a total noob.

Illusion is hands down the best and most powerful school. Think back, what was the hardest/most annoying monster you fought? Those spider daedra that squirted little spiders at you? They would be much less annoying if they didn't paralyze you. Paralyze is possibly the most lethal effect in the game, and its in the illusion school. What else is there? Invisibility! Chameleon! Those have limitless out-of-combat and in combat uses. Also on the list, Frenzy - or... what to cast if you want to loot someones body but don't want a) a 1000gp fine b) to be kicked out of a guild or c) be killed by the frenzied npc. Just bring their disposition down, cast frenzy, draw a weapon (if necessary) and run and cast invisibility. The guards will do the rest, then you just loot the corpse for everything you wanted and bam! insta-win.

Silence - turn any spellcaster useless. Unless they carry a potion of dispel (which yes, I happen to do and would suggest you do too). Light and night-eye - because sometimes you need to see stuff. Last two that I'll mention: Demoralise! Let's say you feel that one of your enemies (or a shopkeeper or guard) would be better if they just ran as far away from you as they could. Very handy. Even handier in combat... Command Creature/Person - this causes enemies to start attacking each other. And the sweetest thing - if you go invisible after casting it and the Command duration expires - they will probably keep fighting anyway. Marvellous.