I wouldn't be without a multitool. Every survival situation I can imagine myself in is a mix, spanning both man-made and natural materials; being stranded in pure wilderness is an anomaly. The ability to fix, build, and improvise is priceless--and that includes the day-to-day stuff of living.

If I'm doing heavy work, I'll add a stout folder, an axe, a 10" vise-grip, a chainsaw, etc. etc. Then, the multitool fills in the gaps.

The Leatherman Wave II is the one I always come back to. It's strong, comfortable, and very versatile. I use the pliers constantly, the blades on occasion, and the other tools on an irregular basis. When I need to go "urban" I clip on the excellent pocket clip and forgo the belt sheath. But I would feel undressed without this "package" of possibilities close at hand.