Dragonskin

Dragonskin is a very powerfull power in any race's arsenel, However because bretons are by far one of the best Magic classes in the game it was given to them, as apposed to their oblivion cousins who just got a higher resistance. This power when coupled with the alteration ritual spell basically makes you into a tank for 60 seconds. Dragonhide which makes people hit you for 80% less and Dragonskin (coupled with the bretons passive of 25% magic resistance to all magic classes) gives you a massive 75% resistance to magic. 50% of that gets absorbed into your magicka.