I have to be ready for about anything, so my /chests are always filled with my essentials.
Chest 1:
[ATTACH=full]26006[/ATTACH]
My god armor, my god tools, books for enchanting (lapis is in my echest), melon slices for quick food when I go hungry, and that red dye is named "The Lady's Broken Heart" for when people kill me for whatever reason.
Chest 2:
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Swiftness potions, melons, boat, compass and epearls for going after the supplydrop, gold/torches/rails/minecarts/quartz slabs for making villagers (there should be gold apples here too), and night vision potions for whenever I go mining or something.
Chest 3:
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Valuable heads (adloves/Dawn/BlendyCat) and milk buckets to get rid of potion effects that I don't want (i.e. guardian temples) and then a ton of space for if I ever need extra space like if I went to a drop party or something.
[Extra] Enderchest:
[ATTACH=full]26009[/ATTACH]
Where all my valuables are. :)
I have to be ready for every single situation just because I'm paranoid like that :P I clear my /chests about every time I get back from a wild trip or something just to keep it pretty free.