So, I really wanted to do a pure mage. This, as many of you know is totally impossible due to the [censored] of destruction magic. So, I'm doing a Hybrid. So far, I'm thinking of doing something based on Morrowind classes. I'm definitely doing an Argonian, focused on Conjuration. Here are the four that I find interesting as bases, with basic skill layouts:

Witchhunter
Archery
Conjuration
Restoration
Alteration/Light Armor

Sorcerer (help, I need some on this one.)
Heavy Armor
Conjuration
Enchanting
Restoration

Battlemage
One Handed (Axes)
Conjuration
Restoration
Heavy Armor

Nightblade
Sneak
One Handed
Conjuration
Illusion

EDIT: I have Dawnguard, for whatever that's worth

Pure mage impossible? Well I guess I better stop being one. Darn it.

Care to share a build? I'd love to do it if you know how.

Pure mage is viable, probably more so than anything else. Once you get dual cast with destruction you're more or less unstoppable if you've the magicka to just keep doing it. Pair it up with restoration & conjuration and you've got a pure mage that can stagger enemies frequently, do loads of damage, heal oneself, and also have summonings to support/tank. When you've maxed all these to 100 you're pretty OP.

If you also get gear that reduces cost of destruction/magicka regen, and there's also a perk in resto that gives you magicka regen I believe, you'll become strong to a point where expert will be a cake walk. Wether you use heavy armor and enchant it with what you need, or get robes (the archmage robe at the end of the winterhold college is super strong for example), then you'll be even more powerful.

Truly? I'd really like to do this. Am I wrong in picking 4 majors?

I have an Altmer mage for their Highborn ability and the extra 50 magicka. I focus on Magicka of course. The skills I use are just Destruction and Conjuration. Those two are all I really need to win my battles. But then again I have my College quest gear so that helps a lot. Pure mage is perfectly viable if you focus on the right schools and have some decent gear.

Edited my post abit. To answer your question; no. You gain perks all the way up to lvl 81 which is certainly enough to fill 4 majors, and more. Just keep in mind as you lvl up to not spend all of your lvls on magicka alone, you do need some surviveability still. If you now think "I thought I stop gaining perks after 50?" then you're wrong, this was changed just before the game was released.

Do you find yourself focused on surviving through just your pets or do you feel you contribute with your spells? Is Altmer mandatory? Do you have your gear self enchanted or found? I really am curious, please don't take this as sarcasm or something.

EDIT:
Aravy, thank you very much for your input! BBetween you two, I think I can put together a damn fine wizard. I <3 these forums.

I find myself contributing a lot with my Destruction, usually my pet just tanks for me while I mop up the enemies. Altmer isn't mandatory no, but I like it most for pure mages, I'm sure a Dunmer would make a good pure mage was well with their Destruction bonus and all. Most of my gear is from quests or chests. I have my gloves and boots enchanted by myself though, Enchanting is very useful. Oh no worries, I enjoy giving advice and the like.

I'm glad you're finding this useful.

Well, at occasion I do play my battlemage as a pure spellcaster, my conjuration is at lvl 90 so I've a storm atronach to tank the stuff. What I do is simply pop him infront of me, step back, and start casting single fireballs. If anyone approaches me, I can just dual cast and stagger them. My conjuration is certainly not enough to take on enemies alone, as he doesn't do alot of damage, but paired with my destro spells I plow through most enemies. Altmer isn't mandatory, I play a dunmer mage, and as such I get a really powerfull resistance to fire, which helps alot vs other mages, also we get a destruction bonus

My gear is ebony, I don't do smithing so I don't really have acces to deadric or dragonbone except for the small chance from dungeons. I've enchanted this with reduced destruction cast primarily. I've also enchanted my boots with frost resistance, so I'm resistant to both fire and frost, which are the most common spells. Also, you might want to get the dragon mask Nahkriin, as it gives a really powerful destruction and restoration cost reduction.

Edit: You're welcome!

So a pure mage layout might look something like

Conjuration
Restoration
Destruction
Enchanting (I don't wanna wear anything stiffer than cloth, if I can avoid it)

Yup. Remember to get wards as these will help you survive vs other mages drastically should the atronach fail to keep the aggro of someone or he dies. Also keep in mind that some mobs might be abit hard, like bandit bosses and draugr death overlords, but this is the case with everyone. As you start lvling some and learning how to play a pure mage, you'll start doing really well.

Edit: Atronach is definitely the way to go btw, they're cooler and overall better, particularly the storm atronach that has magic attack & AOE attack, and is really tanky too.

That looks good. I'd say you're good to go. If you'd like the Mage Armor perks which are very useful, invest in Alteration. The armor spells and Mage Armor perks give the caster some great defense. Though I find myself not using them, since I have my Atronachs.

I think I really don't need to be all that tough as a wizard. It's gonna either be enchanting or alteration. Which is more useful in the long run?

I'd say Enchanting. Alteration is useful when you plan to be taking some damage, when you're a Conjurer you wont be.

Alright! Thanks you guys, I'm gonna go build this guy. Ima call him Milos.

Well my current pure mage build i maxed alteration and destruction at level 35 (with 6 main skills, let alone 4). Alteration is pretty badass, but if i were you i wouldnt pick between alteration and enchant, rather id pick both. If you add enchant as well as alteration you'll still max your main skills pretty early. I havent been able to get a pure mage to level 50 yet because i max my main skills by around level 40 and i dont want to pick up new archetypes just for the sake of leveling.

You'll probably end up with enough perks to get what you need from both. Remember that you don't need all the perks from all the skill trees you choose to major. You can keep alteration abit at the back and focus on your majors, popping a few points into it, I believe mage armor & magic resistance is pretty early in alteration. Wards are restoration however, so there's no harm in picking up such a spell.

No problemo, glad the advice helped. He'll be a good pure mage, what race did you finally pick?

Yeah alteration is one of the most useful skills.
You got 3 perks that give you 30% magic resistance permanently.
3 perks that make it so ebony armor spell give you 300 armor instead of 100 if not wearing any armor.
A perk at level 100 that makes it so you absorb magic 30% of the time, adding the magic power of the spell hitting you to your magicka pool while taking no damage.

Indeed.

Summon atronarch, spam stagger-spells. Congrats, you just won a legendary dragon on master difficulty!

I'm probably a Witchhunter but i will use Sword and Board too when discovered, and i won't use restoration unless i've just finish the battle...

Exactly

Pure Mage possible but you should have some support skill like illusion.

Conjuration is one but they die easy against boss. Having illusion is recommended especially dual cast perk allow you to affect enemy much higher level.

Also keep an enchanted dagger for backup. You don't need high level or perk in one handed. Just rely on attack speed of dagger combine with enchantment.

Also alteration is you get to very high level you can paralysis almost anyone. At this point you are invincible