I like the Squirrel_Killer's guide. (the ultimate game breaking defense one) If you're not running any mods that alters spells and perks like SkyRe.... necromage vampire.... getting necromage (restoration right?) as a vampire and then the atronach perk (alteration?) and then the atronach stone (all in that order according to the UESP guide, otherwise you'll not get the full bonus) == 100% permanent spell absorption. Then go with light armor (up to dragonscale) with of course your choice of 100% <that school> cost reduction. I think You might even fit in 2 schools if you enchant enough items, not sure what items though. Become Ethereal and dragonhide (with proper perks and dual casting would help grant you additional defense, well.. you can read the whole guide
http://skyrimforum.com/threads/squirrel_killers-ultimate-guide-to-game-breaking-defense.21541/
But if you don't feel like going that ultimate defense route, I would recommend a necromage vampire anyways just because that perk alone grants you so many bonuses to everything... your current spells you use, your crafting (alchemy, enchanting, smithing)... should think about it is all
Note: The guide wasn't actually specific if getting the atronach stone or perk first would affect it, I just assumed it would be in this order, but necromage must be taken first for it to work if you go this route