I like Spell breaker. What's great about it, (with exception of Daggerfall) is that it has more or less kept the same shape since Morrowind.
the Daedric Crescent, closely followed by the Spear of Bitter Mercy
EDIT: ohh from Oblivion and Skyrim? Azuras Star i guess
The only one I've ever used is the Ring of Namira. So, I guess, "Ring of Namira" would have to be my answer.