IMO water will be top priority so I carry one of these
http://www.campingsurvival.com/lifestraw.html
Also your initial bug out food will be important don't skimp on this, calorie is king, you are going to be burning up a lot of energy.
A first aid kit tailored to your area and needs. For example if you have a lot of poison ivy or oak around you take something like this
http://www.teclabsinc.com/products/poison-oak-ivy/tecnu-extreme
A good knife, 550 paracord and tarp.
Also don't rely on one source to make a fire. I can make a bow drill set and make fire with it, but so what that is last resort. I have fire steel , waterproof matches, and several lighters. I will also spread them around between pants, shirt, jacket and socks in case I loose my bag or jacket I'll still have a way to stay warm.
Expand from there if you have room or want to carry more.