I'd have to agree with a pp, the ride that scared me the worst was Alien Encounter. I was so freaked out that I leaned as far forward as my restraints allowed me and had my eyes shut the entire time. My husband loved the attraction and tried, in vain, to get me to go back on it.
But, now that AE is gone, I don't think there's any ride that scares me too much. I LOVED ToT. Dinosaur made me jump a bit, but I loved that one too.