I agree that people carry around extraneous things in these kind of bags. I'm going to use it for trauma kit, shelter and cordage, fire starting, food and water, knives, multi-tool, possibly a small utility hatchet, headlamp, and clothing, fishing kit, and sewing kit. I'm working from a list and tweaking it to fit my needs:
Keychain tape measure
Keychain thermometer
ITW Tac Links
Fixed blade - HK Conspiracy (plain edge)
SOL Emergency Whistle
Weight Bearing Carabiner
Bandanas
Generic 'Altoids' Tin
UCO Waterproof Matches
Bic Lighters
Magnesium and Ferro Rod
SOL Signal Mirror
Large Sewing Needles
CRKT Eat N' Tool
Mini Sharpie
Multi-tool
Repel bug spray
Clear 50 gallon garbage bag/drum liner
Mountaineering sunglasses
4 sticks of beef jerky
Travel, compact Bible
Husky crank flashlight
Streamlight Task Light
Black Diamond headlamp
Mechanix gloves
Hand warmers
Batteries in box (AAA, AA, C, and a small screwdriver)
Coleman meal-in-a-bag
2 Wetfire fire starters
3 pens
1 highlighter
2 Motorola Talkabout Radios
Small pad of paper
Blackhawk Roll-out Medical bag
Outdoor Gear dry bag
ITW XL Zip-lock bag
Trucker's Friend Utility/Demolition Tool
Klean Kanteen and nesting cup
Wire -- light and heavier gage
Zip ties
Small sewing kit
2 Large
100 ft. paracord
50 feet paracord (high quality)
50 feet paracord (lower quality)
Compass
Banana Boat SPF 50 lip balm
SOL Sport Utility blanket
Fleece jacket
Level-2 long-sleeved EMS shirt
Extra wool socks
Northface fleece hat
2 large, heavy duty rubber bands
Dental floss
Rubber bands
Swiss Army Knife
2 smaller needles
Potable Aqua (water treatment)
Poncho (red)
Wool gloves
Boonie hat
Neck warmer/sniper wrap
Dust masks (3)
Toilet paper
Duct tape (2 rolls/2 colors)
Hand warmers
Emergency reflective blanket
stomach mediine Diarah stool softener Tums
first aid kit