I haven't seen the Svord Peasant mentioned yet. They come a bit rough, but there is a great blade in there if you are willing to sharpen it up and make it how you want.
Although, honestly the only two that I feel that everyone should actually own/try at some point are the Opinel and the Mora. They help set "baselines" for what is expected/needed/wanted in a knife. If you want an outdoors blade, the Mora is always going to be brought up. You buy it, try it, and either 1) love it, and never move onto anything else, 2) like it, but want to try something different, or 3) hate it, and get rid of it. I expect most people fall into group 2, and as such they will probably know what they want different.
The opinel is similar. Its a great example of what a pocketknife should be imo. Not saying other designs aren't good, just saying that the Opinel is solid, comfortable to use and slices well. Once you try one, you'll likely end up rating future knives cutting performance relative to it, and will have an idea of what other features you want (i.e. one hand opening, etc).
Cheers

.