In Trigger, I always liked the Safe Helmet. It gave my casters some much-needed defense, since when I was on my 3rd playthrough, Lavos decided not to use a special move on every turn. Instead, he decided to slap my two casters, leaving poor Crono by himself.
And, I always thought Nova Armor was waaay better than Moon Armor. Moon was just some high defense, while Nova kept you from getting Chaos, Sleep, Poison, or anything else (didnt work on Lock, strange...).