Not sure if the advice so far has pinned it down for me. I remember (from 30 years ago) liking Big Thunder Mountain and being really sick on Space Mountain.
So, I certainly don't want to do anything that approaches the intensity -- from a roller coaster perspective -- of Space Mountain, or that exceeds it.
On the other hand, I'm not worried about things that are merely scary because they jump out at you -- Yetis, dinosaurs, etc.
It is more the jerkiness of the ride, perhaps the height, certainly the sensation of falling -- I don't like that.
So I will be skipping Space Mountain, Rock'n'Roller coaster, Tower of Terror, Mission Space, and anything that gets me wet.
But I will be going on Big Thunder and, from what I've heard, Dinosaur.
So that just leaves a big question mark about Expedition Everest. I really don't want to get motion sickness. Maybe I should just skip it.