If you want an old style pocket knife with some intresting history, get a Douk-Douk or two. They come in a couple of sizes, and the small one is flat enough to go in a wallet. The medium rides well in a side pocket, and the blades are thin and can get very scary sharp. I think it was Lee Valley tools that had a speacial recently two for 30 something dollars, a medium and small.
The Opinel is an exelent knife, but as mentioned they are a problem if they get wet.
The sodbuster is a personal favorite of mine, and cuts as well as some of the afor mentioned. Wide flat ground blade gives very good geometry for cutting. You can find a wide variety of makes, from U.S. and German makers. Case, eye-brand, Kissing Krane brown mules, Queen country cousin in D2 and maybe still 1095 though I would'nt put money on it. There's alot of working types that rely on a sodbuster.