A good pocket/utility knife and sharpening set. You don't need to spend hundreds, but my favorite is my Spyderco Para 3 Lightweight. It has a 3 inch blade, weighs 68 grams, and it's made of BD1N steel which keeps an edge very well.
+1 for Spyderco Para knives especially if you can find the sv35vn steel. I can't speak to the bd1n but Spyderco generally uses extremely high quality steel. It's an expensive knife but it's well worth it for the quality.
I wish I knew they didn't come in S30V or anything when I got mine, I would have looked for something else since I had never heard of BD1N, but after carrying it with me for 2+ years I'm actually pretty happy with BD1N.