If I wandered outside right now, with nothing but a knife, and the clothing on my back. I'd break a window and come back in, 'cause it's cold and snowy, and I'm in a pair of sweats and a T-shirt.
But, were I to suddenly find myself outside, in the clothing I wore when I was outside a few hours ago, I'd have had two knives on me, and with both, plus the metal match in one pocket, and the flint&steel box in the other, I could have started a roaring fire, dug me a snow-cave, snared a few bunnies, and shown back up in time for work tomorrow...
Now, if we're talking survival, there's a few things I want to be able to do. If you limit me to a single tool, make it one that can do all of them (My swisstool can, but not all very well)
I want to be able to make small shavings for tinder.
I want to be able to get to the middle of a standing tree, for dry wood in a downpour (Saw or chop, I don't care)
I want to be able to make a flat piece of wood, and cut a notch in it (A fire board, for a bow and drill)
I want to be able to sharpen my blade (I can use a smooth stream-stone if need be, and the blade will take the edge)
I want a blade I can wield deftly enough to carve a figure four deadfall trigger.
And last, but definately not least, I want a blade with a built-in emergency transponder, so every time I pull it out of it's sheath, all the local authorities know I'm lost and need help...
Anyways, as I said, my swisstool can do all of those (Except that last one anyways), though some take more ingenuity than others (Instead of using the knife to split wood, I can carve a wedge, and use it to split wood). Any blade/tool that can accomplish those things, is one I would be happy to carry with me, and feel as comfortable as possible surviving with. One that doesn't, merely means I haven't improvised enough yet...
(Thanks Greg, before long, We'll be improvising things out of pocket lint, river ice and a toothpick
)
So you asked about a survival knife. I know a few people that have survived different places, and some carried odd and assorted things (I'd love a shovel, though not the Ox-sashimi). You could ask them what they carried (Though you should shy away from anyone who runs at the marines rescuing them, waving a 9mm) but for me, I'll take whatever is on hand that will accomplish those tasks, and if someone else is paying for it, the more expensive, the better...
Stryver, who wonders if he can fit a tin of altoids in his survival kit...