Nadir, made from Nef and Tir, in that order. This works in two-socket helms of all types.
One of the easiest RuneWords to put together (we got over 200 emails with shots of this in less than 12 hours after we first posted the recipe) and one with some very odd stats. No resistance or hit points, which most require in a helm, but the Cloak of Shadows is very useful. Note that it's -33% gold, one of the few negative stats in the game.
Headgear Runewords