Is it possible to play a pure spell caster and survive the game? Using robes, and not focusing on melee or ranged?

If I tried it, what companion should I use? I'd need a tank type to hold aggro.

I've made it to 21 as a warrior type, but the magic college has me tempted to give it a go as a High Elf or a Breton. Which one is more advantageous?

Play what you like, I play pure mage and love it, No having to sneak around I just walk up to an enemy and dual fire blast there fast off. Great fun, depends how you like to play, and some of the mage quests are amazing.

I'm up to 26 as a "pure" mage. I have a good sneak score, I hope that doesn't disqualify me.

I don't bother with a companion. I either use a summon, a raised dead, or frenzy to tank group battles. And destruction's stagger will tank any solo battles on its own.

I would run a High Elf (just because they are awesome). And I think you could definitely run a pure mage. Just put most of your points in Magick and some in Health (I would do a 2:1 ratio). Dual cast some novice spells (they are better than apprentice level spells imo) with high enough magick while mizing in shouts and you will be fine.

Also, the robes you can get add huge bonuses to your magic stats, plus Gauldur's Amulet will help.

Yeah, anything goes. If you want to min-max everything you can do better as a warrior type, but this is a singel player game and mages certainly work too. I play as a pure mage and it is great fun. I do sneak a bit though, unlike the poster above. At least if i dont have a follower with me that can help me out in battles.

You shouldn't need a tank to help you out at all.

I've been playing a pure mage for my first playthrough on Adept and I haven't had any problems, with a bit of tweaking I'm sure it would be fine on the higher difficulties as well. All of the people complaining that magic is underpowered are looking at base damage and mana cost alone.

With a bit of strategy and some proper gear you'll do fine, Flames does amazing damage per mana cost.

I'm playing as a pure mage and it's actually pretty easy for the most part.

The one thing you won't be able to do is stack all the crafting stuff on top of itself to produce insane numbers, but if you want to play the game in an un-broken way it's perfectly valid.

Yes, but don't get scattered. Make sure you choose early on your 2 primary skills and always improve those as much as possible first.

I'm doing destruction/alteration, but I bet conjuration/illusion would work pretty damn well too. Some points in restoration, and I haven't decided quite yet which of alchemy/enchanting to dump extra pp into.

As a 'pure mage' you need to get somewhat creative with combat strategy. Running around spamming fireballs didn't work too well for me; as fire/alteration I had no way of controlling big fights. To fix this problem, now I'm trying Ice. I've given my companion a fear/drain stamina weapon and a bow with a fire enchantment. This combo works extremely well, a pleasant surprise since I typically really dislike fear effects. Basically, when the enemies come in close lydia sends em running and drains most of their stamina. Even for more difficult opponents, a well placed dual-cast ice spell brings them to their knees and they're still quaking in fear.

Summarizing: if you're a 'pure' mage, make sure you don't just focus on offense/defense. Make sure you have some control mechanism, or you'll have trouble.

I'm a level 16 high elf. Most my level perks went into magika, with a couple in health.

So far, its been very fun. My main method of destruction is fireball, with some occasional conjuring of weapons.

Lydia is with me now and she's useful sometimes. I don't NEED her, but it's fun having her with me, anyway.

I suggest Breton. The inherent magicka resistance is very useful.

Alchemy potions for magicka and health recharge are important. If you decide to develop Alchemy, don't wait as I did. Start eating stuff right off the bat to learn the first effect. Mix and match the stuff you have the most of with other stuff to see if you get hidden effect matches, Or you could wait until you get the perk for mutliple effect reveals; I prefer knowing earlier, though.

There may be times when you need to recharge magicka or health quickly mid-battle, so that's why the potions are important.

Also, don't neglect simple potions like ones that boost bartering prices. The payoff is worth it in most cases.

You wouldn't be worrying about the Poison line of perks in this approach, of course. Those perks can go in Enchanting or Destruction, or some other school (I'm focused on Destruction right now).

I am a brenton and I put all my points into magicka. I have the khajiit from the college of winterhold as my companion, as far as tanks go, I use conjuration to summon something to take alot of damage. Also Stoneflesh or Oakflesh increases your armor rating, so that helps.