So it occurs to me that before I can actually make a list of items to stock systems with, I first need to decide what sort of systems to stock. There seem to be several options:
Highsec: No. Just no.
Lowsec FW area: Putting a bunch of people in a clearly defined volume of space and having them shoot at each other should make for a wonderful trade opportunity. The downside is, I'm pretty sure everybody else knows this too. I would tend to anticipate a lot of competition, and getting in on this would probably involve first learning about FW.
Non-FW lowsec and NPC nullsec: These areas should give me larger margins, but one expects the volume to be much, much lower. Bonus points, though, for less frequent restocking. Access to player sov stations would be optimal, but I don't have that.
Nullsec entry systems: One expects stocking these could result in higher volumes and higher margins than many other highsec/lowsec systems.
Incursions: I don't at all feel like chasing these around.
In theory I can stock between 6 and 11 systems, depending on how thorough I want to be, so I'm not restricted to only one of these options. Lots of research to do, I guess.