If it is indeed true that you can have only 1 cutting tool, then I'd opt for a Leatherman Charge Titanium, a Leatherman New Wave, or a Leatherman Supertool 200. My onw choice would actually be the Supertool 200. It's around $50, has a saw blade, a plain-edged clip point blade, and a serrated sheep's foot blade. It also has a two-sided file, an awl/punch (useful for trap/snare making), and the other standard tools. Plus, the tools all lock; I don't personally like using a multi-tool that doesn't have locking tools.
The up-side to the Charge and the New Wave is their very comfortable handles. The New Wave also has 154CM blade steel, which is a nice touch.
If, by some chance, you can bring both a multi-tool and a knife, I'd take along the Benchmade Activator that was previously mentioned. To me, handle comfort would be of utmost importance, followed by reliability. A fixed blade would be tough and the Activator has a good-sized handle on it.
Good luck in your endeavors
