I go either unarmored, or Heavy Armor, and Robes, because Evasion seems to be better defense than passive AR. (Also, there's little mage friendly Light Armor, unless you make your own. If you're enchanting, that might be your best choice for the Stamina recovery.) Use the sword to finish them in 1 hit, maybe with Flame Cloak, or Critical Charge to stagger them with a power attack. Stay out of the melee for the most part, running around blasting mobs, and just kill them up close. I've also found an Axe more useful than a sword with the Hack&Slash perk to finish off the ones that aren't quite killed in 1 strike. Paired with Fire's DOT, from your spells, cloak, and enchantment, you can keep running, and let them die while you come around for another pass on their friends.
I don't do rigid H/S/M ratios. Put it all into Magicka until you start feeling squishy, then invest in Health, or armor until it starts to clear up. Stamina, as much as you need, but I usually get away with 130 (with the Gauldur Amulet.) Conjuration can be extremely helpful too. Another possible route would be Alteration, in lieu of armor, or to enhance it. Bolt Archers first, and stack up as much Magic/Elemental resistance as you can. For this, I suggest Breton, Redguard, or Altmer, though Imperial wouldn't be a bad choice.
I like:
http://skyrimcalculator.com/#161668 to start. (Note, I left Armor open, but with Heavy/Robes, and the Lord Stone, you won't get 1 shotted if you keep moving.) Train up Destruction burning Draugr, because they take more damage from fire, for more Experience, then switch to Lightning to zot Dragons. After that, start working the Forge, and Arcane Enchanter to improve your Weapons/Armor, focusing on Absorb Health (do the College of Winterhold for the Drainblood Battleaxe to disenchant, and so much more.) The Drainheart Sword is a good drop in for the off hand once you get Dual Flurry/Savagery. This is for when you get stuck without Magicka, or surrounded where Flame Cloak is your only effective magic. Also, run the main quest for Nahkriin, and Shouts. Wuld is the best for quick getaways, and manuevers. Fus to mass stagger (don't RoDah, because that can throw them out of reach/range, unless cornered. Most shouts recharge faster if you just use the first Word.)
Fire/Lightning Bolt (depending on the target) Fireball, Ice Storm (Mostly to slow everyone) Flame Cloak, once you open up Expert, upgrade to Incinerate, Thunderbolt, Wall of Flames (To kite mobs over) and Disintegrate. I usually switch to Conjuration when the damage starts to cap on Destruction. I can make do with 130 health (or more with other enchantments) and All Magicka, but if you go for Altmer, they run the fastest, and get a head start with Magicka, so you can spend the first few levels on Health. If you do go for Light Armor, start Smithing right away, and work up Enchanting with staffs. The Armor of the Old Gods has a Destruction Bonus, and the headress adds Magicka, but you want a female avatar to avoid the deer head look. You can do a Staff/blade combo with Jyrik's and not worry about Magicka at all with a good soul trap, or firey soul trap weapon. (Assuming you can defeat Warlord Gathrik.)