I know I am posting late on this, but, I wanted to put in my .02
One thing that I hardly ever see mentioned in a kit is a visual signaling device, such as something brightly colored. I am part of a search & rescue team, and you;d be amazed at what people wear into the woods. No one ever carries a cheap, walmart hunting vest. It costs all of $5 or so, you can put it into a pocket, and, the hunter orange can be seen alot easier than a green gore-tex jacket.
As far as what you carry; you're only as good as the knowledge you posess. I know its been stressed numerous times, but, you can carry whatever you like; if you dont know how to use something, it serves no purpose. I live in New England, and, theoretically, I am only a day or two's walk from civilization in any direction. So, my priorities would most likely be shelter, and possible a fire (barring any medical emergency). Now, in N.E, the easiest shelter to build would be a debris shelter. We are rife with large boulders to build one next to. Again, practicing building one, will make it easier when you HAVE to do it.
As far as fire goes; the hardest time I ever had building one was with the bow technique. It took the better part of an hour. But, I know I can do it, if needed. Anyone can light a fire with a lighter; to build one with an alternative method requires practice, & patience. Something you want to practice, again, BEFORE you're in that situation.
Closing, I always have a 34 hour pack in my jeep, in the event of a call up. I am in the woods alot hiking, geocaching, and whatnot, and still carry the essentials with me. As soon as I get my new cam, I'll post up pics of what I usually carry.