If you're counting chain mail armor, I almost have a full set now from my skeleton spawner. If not, I just got a power 2 punch 1 bow from a skeleton, but it's pretty badly damaged. I don't think I'm going to repair it, since I can just craft my own, but it's pretty cool.
Chain armor is definitely the rare drops that I want the most and the best in my opinion. I've gotten a bunch actually in my YouTube let's play world from my zombie exp grinder. Zombies used to drop iron shovels all the time and that was cool
Feather falling III chain boots was a good one.
I also have a good gold helmet that I think is respiration III and some protection enchantment.
(I use that helmet while measuring a lake so I can build my floating island to match the lake's topography.)