I'm not into thrill rides at all, but, I love IOA and US. US has alot more tamer rides and Jimmy Neutron is not scary at all! You sit and watch a movie and your car moves up and down and shakes. There are certain car's that don't move and you can just site and watch the movie.
IOA I love for it's theming, I like the Popeye and Bluto water ride, the Juraissic Park water ride, Seuss Landing and Spiderman.
US I love MIB, Back to the Future, Jaws, Twister, and I even rode the Mummy ride, which if your not into thrill rides, I probably wouldn't do it. I wasn't really scared but, just a little nauseous when I got off.
Have fun!