The idea is to keep your survival gear pack handy so that means small & light so you'll always take it with you! You have to use some common sense when putting your kit together and adjust your gear for needs that you anticipate - hot weather/cold weather issues and the like. It needs to consist of items that will help you deal with medical emergencies and stay warm & dry for a few days. I always carry a map, compass, flashlight and knife on my person so let's start there. The items in my pack include the following:
Small First Aid Kit (for minor things plus some butterfly strips)
Water
Several ways to make fire (small lighter, waterproof stick matches, flint striker)
Fire starter (commercial or home made)
Plastic poncho (to cover up)
Space blanket (to sit/lay on)
Large garbage bag (ground cover, poncho, shelter roof, etc..)
Parachute cord (big jobs)
Dental floss (small jobs)
Knife
Multi tool
Whistle (you can hear it a lot farther than a shout and you never get tired of blowing it)
2nd Flashlight (small L.E.D.)
"CL"