CSG - Fair point about slippies, but my PSK is for genuine edc, and where the laws are restrictive, a sak fits that need. I pack a lumberjack, which gives me a good sharp blade and a small woodsaw.

I also (as per other threads) keep a space blanket or plastic poncho with me for shelter because it folds down to the size of my kit and attaches to the tin with rubber bands.

And I agree - a decent waterbag, puritabs and something to make a cookpot (I use a loaftin folded and hammered flat) are essentials.

It all makes a compact package that I can slip in a pocket and isn't dependant on me having anything else with me (I usually do, but that just gives some redundancy)