I keep an Eberlestock bag in my truck, but I don't carry it with me around town (I'm retired). It has the following items:
Knife
First Aid Kit (bandages, Neosporin, Tylenol, hand sanitizer, etc)
Israeli Bandage
Qwik Clot
Carb bars
Compass
Water
Water purifier
Polartec Sweater
Binoculars (10X42)
Cordage
Emergency sleeping bag
Probably a few other things I can't think of at the moment (and I'm too busy right now to go get the bag). I also keep a thermal blanket in the vehicle, along with spare ball caps, extra water, baby wipes, etc. The pack is also fitted with a Safepacker holster, since it's impossible to draw from my normal holster with the wide waist belt from the pack. This keeps the pistol concealed but makes it almost instantly accessible.