Bradford, my usual packraft-specific gear for a summer trip in the Bob is a Yak with a cruiser deck, 4 piece paddle, simple foam PFD (you can get decent ones for 40 bucks), inflation bag and repair kit, 2 6' lash straps (with ladderlocks), and raingear. If the forecast looks a little on the cool or wet side I add a fleece shirt or vest. That's it.
I don't like paddling specific splash gear because it's heavy and sucks for hiking. An exception is a nice neoprene waistband on your rain pants, which helps keep out leaks. I added one to a pair of side zip Goretex pants.
I like the security of the foam PFD. I have a goofy little inflatable snorkeling vest, but pretty much bring the foamie all the time.
I'd bring a helmet and throw bag if going through Three Forks and Spruce Park on the lower Middle Fork, and maybe a farmer john wetsuit if the weather was especially cool.
Much of the time on sunny days (like this past weekend on the South Fork), I'll just be wearing board shorts and my windshirt (more for sun than anything). Raingear might go on if you're floating right from camp in the morning, but it often is warm enough by 11am you won't need it again until late.
I should say that folks who run colder might disagree.
.
