Duffle bag (or other soft luggage - no hard-frame backpacks), sleeping bag, sleeping pad, waterjugs (enough for one gallon per person per day- or water filter), gloves, poncho (or rain suit), low folding chair, binoculars, cooking gear, provisions, plastic bags (ziplocs and trash), rope to secure supplies, sunglasses with strap or leash, litter bags, old tennis shoes (or water shoes or socks), sunscreen lotion (SPF 15 or greater), chapstick, flashlight, bug repellent, wide brim hat, long and short pants, lightweight long and short sleeve shirts, medium weight jacket, swimsuit, towel, personal toiletries, camera (waterproof or single-use), first aid kit, maps, fishing gear, small tent.
For most Colorado River canoe and kayak trips, nothing beats an old-fashioned duffle bag. GI Style canvas, zippered nylon or cotton, any near-standard duffle bag is great. If you have one, a Boundary Bag is even better. Food and cooking gear, as well as tents and tarps can be separate, but all personal gear, including sleeping bags, foam pads, clothes, fishing gear, etc., should be put in one duffle per person.
Line the inside of the bag with two or three plastic trash bags - NOT THE OUTSIDE. Then line the bag with your sleeping pad. Stuff your sleeping bag inside on the bottom - as TIGHTLY as you can.
On top of your sleeping bag, pack your clothes, toilet articles, fishing gear, cameras, etc. (zip closure type plastic bags are handy for many of these items.)
That's really all there is to it. Close the plastic trash bags with twist ties, then zip up the duffle bag and you're ready to go. You may want to put a few extra plastic bags in on top, so you'll have extras for later in your trip.
TENTS, TARPS, STOVES AND FOOD
Pack these items in boxes, duffle bags, mesh bags or plastic coolers (ice chests) as appropriate.
CAUTION: NOTHING should have plastic bags on the outside. They will tear immediately and end up next to useless.
Bring everything you need to make your trip pleasurable. A canoe full of loose gear is an accident waiting to happen. Duffle bags and canoes were made for each other. Try it!
Backpacks are great on the trail, but a hard-frame pack is a misery in a canoe or kayak. These packs do not work for paddling - the frames will be damaged, and you will be frustrated.