Legedary Creature - Angel
Spells and abilities your opponents control can't cause you to sacrifice permanents.
This card is just funny, in the good way. Protection from spot removal, protection from Tribute to Hunger, and protection from Liliana of the Veil. In Innistrad Block, you better be packing a Blasphemous Act or it might be "gg" for you in a couple turns. For 5 mana, I think Sigarda is at that perfect casting cost and she's going to see a lot of play... as long as the post-Intangible Virtue/Linger Souls environment is still letting games progress past turn 5.
Ever since Serra Angel & Fallen Angel, everyone and their mother has tried to make an angel tribal deck. The problem has always been that there was nothing really tying them all together except for flavor. There are no playable angel lords to speak of... but maybe this will change? If there was ever a time to make tribal angels playable it would be in Avacyn Restored.