I got an actual paddling life vest! The comfort is worth every penny!
I also got a large waterproof duffel bag with backpack straps. It makes packing and unpacking the boat for a landing, launch or portage much easier and will keep me from losing a bunch of loose small items if I roll the boat.
I got backpack cooler for the same reason. On the previous trip we had a normal cooler and accidentally dumped it in the water, losing half our ice and filling our cooler with dirty river water. The backpack one zips up and I use freeze packs instead of loose ice.
Now I have a good system for my big tandem canoe. One of us wears the cooler on our back, the other wears the duffel bag, and we have both hands free to carry the boat horizontally with the paddles and life vests inside. Hooray for only needing one trip to and from the car and over portages!
Oh, and very light, very packable water shoes and a waterproof phone protector bag so I can keep it on my person in case of emergency and in case of quick photos.
I'm pretty happy with my core necessities like my hammock, sleeping bag, stove, etc so now I can focus on comfort items.
And one more thing! It's a minor convenience, but it makes a big difference. I got a mesh laundry back to store all my life vests in. It makes it very easy to grab and go, and keeps all the straps and buckles from snagging on things.