Ian, a lot depends on how you plan to use the knife, what blade length best suits you, and even which knife feels good in your hand. But you've got plenty of options.
A good example of a folding knife that’s right for travel is the Kershaw Shallot Serrated Knife ($80). Its stainless-steel blade is just over three inches long, with serrations near the base for extra cutting power. The blade and handle are coated black for corrosion protection and to reduce the knife’s visibility. It's a good choice for all-around cutting and outdoor use.
For a really compact knife, take a look at the Benchmade 556 Mini-Griptilian ($85). At just under four inches in length while closed, it’ll clip to a belt or fit easily in a pocket. But its blade, made from tough stainless steel, is three inches long and will cut almost anything. It opens easily, too.
For something a bit more economical, Columbia River’s Mount Shasta Knife ($36) offers specs much like the Griptilian, only with an all-stainless body rather than a grippy synthetic handle. But it still has friction grooves to stay your hand, opens ambidextrously, and looks cool.