Another Kroenen fan here.
Also always had a soft spot for the Crimson Ghost mask from the '50s republic serial, later appropriated by the punk band Misfits.
Oh and Rorschach obviously.
OK, this may not count as it's animated, but, the Phantasm mask from Batman: Mask of the Phantasm. Simple, elegant, and sort of a industrial Gothic retake on the Death look that was accentuated by the scythe like arm weapon.
I'll also throw in votes for Darth Vader (I prefer the Star Wars version over the Empire, Jedi, and/or Sith versions), the Stormtroopers, Tusken Raiders, and Boba Fett.