It depends on your skill in sharpening a blade. I, again (as everyone already knows probably) advocate the inexpensive Smith's Diamond-coated pocket-sized hone steel. $5.98 at Wal-mart. You might also want to have something for touch-ups in the field - I sometimes put a pocket size Arkansas fine (white) stone or a Shrade honesteel in my bag too.
Otherwise, get the Lansky Quick Fix 2 Step Knife Sharpener. I just don't like using tungsten carbide to sharpen my knife. I found the similar Smith's carbide sharpeners to be damaging to the blade by not giving the correct angle I wanted. Those type sharpeners just take too much metal off at a time for my comfort, especially when I'm sharpening S30V, which ain't cheap.
If you don't have sharpening skills (like eyeballing the right angle), you might take some old knives you don't care anything about and practice sharpening or putting edges on knives. I sharpen knives alot and keep in practice now and then by sharpening friend's and family's kitchen and pocket knives for free while I watch the tube at night or visit them, etc.
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Me, a vegetarian? My set of teeth came with canines.