I carry a vic SAK almost all the time. I go for mostly the larger size, but it depends if I carry another knife and what I'm doing. The Vic Centurion (or side locking Adventurer) are generally where my preferences lie. But the smaller Tinker is hard to beat. Lots of folks like the Pioneer. I think you would be generally covered by any traditional slip joint equal to or larger than a peanut pattern.
My opinions relate to general carry and day hikes from a base camp (usually car camping) or one and possibly two nighters where weight is not the dominant rationale for making choices.
Hard to beat a Spydie Delica or Endura for a modest knife that is durable and dependable. I prefer the Delica (smaller), but that's me.
I do think you should consider a Mora Companion or something similar. Good value and useful. Call it part of the education. I personally prefer a more robust 4-6" fixed blade. You'll figure out what you like and don't like. But the Delica, Vic's, and Mora will get to started and cover most of your needs. Pinnah makes good recommendations; I just never tried a Opinel yet. But the multi-tool suggestion is sound for back packing for small non-routine cutting tasks and potential equipment repairs.
Just to clarify... While I personally like the Opinel, I'm not recommending it, per se.
I think any folder with a blade in the 3" to 3.5" range and that is reasonably light (say, under 4 oz, preferably closer to 2 oz) makes sense. Some knifes that make sense to me:
+ Victorinox Trekkers (the long ones)
+ Esee Zancudo
+ Buck Bucklite Max