Once I casted a Paralyze spell on a Giant while I had a Dremora Lord out there fighting for me. I have to say, I was screaming like a little school girl on the inside when it fell. So that along with the Dragonhide spell(80% damage resistance) pretty much gives me enough reason to say Alteration is useful. Also, I would like to make a case for Illusion not being useless since a number of you happen to think it is. Illusion is GREAT for stealth characters! Why? Well, I'll give you several reasons. Frenzy spells are great when you feel like you can't handle the huge crowd on your own. Now when will you need to cast this? Most likely it is useful in Forsworn camps and in forts that are occupied by bandits. Also, Muffle and Invisibility are perfect for sneaking by if you don't wish to sneak. Or if you want to sneak anyway, Muffle alone works very well with Sneak as it eliminates any possible sound you could make while sneaking, helping the Sneak skill level up. Not to mention you can take the silent casting perk, which makes for a perfect stealth/mage hybrid. The perk itself applies to ALL schools of magic! Also, the Calm spell is a great way to stop a fight that you don't think will win. Not only will your target stop attacking momentarily, you have time to run as far as possible if you don't want to risk your life. Hell, you could accompany this method with Invisibility. The Fury/Frenzy spells can be very useful in this odd situation I like to get myself into. Since I use Conjuration a lot and have plenty of empty soul gems, I find random animals that have Petty Souls. Once I cast a Fury spell, I can use Soul Trap and then summon an Atronach so that I can get a filled soul gem. I can substitute this method with Paralyze. However, I would have to revert to using Bound Sword, which is fine for me. So really, both schools are useful for multiple situations