I just thought of an interesting question...
What was the best ounce you ever carried? By this what I actually mean is this:
What "nonessential" item did you bring on a trip despite the fact that it added a nontrivial amount of weight to your base pack, but later decided that it was the best idea you'd ever had and thus a good weight sacrifice?
I suppose you could include items that were essential, but heavier than an alternative that you could have carried. For example, if you think the extra 6 ounces of insulation in your sleeping bag is Worth It, you can write that.
I suppose that almost ANY safety item is hard to classify as "nonessential", but if you want to tell the story of how your GPS or spare firestarter saved your life, feel free.