I typically get motion sickness on most rides although I have never actually vomited. Since I have traveled to a lot more parks this past year, it seems that my body has adjusted and I don't get sick on coasters much anymore. Sometimes though, the feeling gradually builds up during the day and by late afternoon very simple rides can be hard to take.
I remember at West Coast Bash last year after riding X and Tatsu a few times during ERT, I couldn't take anymore and had to sit down for half an hour before moving on. The only ride that has ever rendered me sick for the rest of the day was the Rotor at SFMM which gave me a headache that I couldn't shake. (It is gone now right?)
Someone mentioned Star Tours. The blurriness of the screen always gets me as well. Titan & Goliath at SFOT and SFMM respectively both made me blackout for a brief amount of time. As much as I love coasters, there is no worse feeling then getting motion sickness in a theme park. To me it feels rather hopeless and depressing.