What to pack in a Survival Kit

I'd take John Wiseman's (former British Special Air Service, did operations all around the world, wrote survival books) advice. This is his reccomended survival kit (not word for word, largely paraphrased):

-Matches
-A square candle (square just so it fits in best)
-Flint
-Magnifying glass (to start fires from sunlight)
-Needles and thread
-Fish hooks and line
-Compass
-Beta light (a self-powered light-emitting crystal for reading maps, compass, etc in the dark)
-Snare wire
-A flexible saw
-Butterfly sutures (stitches)
-Flares
-"Mess tin" -- small container to keep cooking utensils in
-Flashlight
-Fluorescent marker panel, for signalling
-Survival bag -- basically a warm cozy blanket to wrap around yourself
-A quality knife -- Wiseman reccomends a parang knife for tasks such as gathering materials for shelter, firewood, rafts, and so on, in addition to a smaller knife, something along the lines of a buck knife
-Block of sandstone, quartz, or granite to sharpen knife
-Light but durable tent & sleeping bag
-Food -- simple, healthy food which will ensure you get enough nutrients.