I think that some of the best rides the park has to offer are Kongfrontation, Back to The Future, Jaws, E.T., MIB, and Earthquake. Also, the Twister attraction is awesome as well as the Nickelodeon tour.
If you like shows and interested in how special effects are done go check out the Gory, Grotesque, and Gruesome Make-up show along with the Alfred Hitchcock attraction which details his style of moviemaking. The Terminator 2 3-D show was great and it was taken from the Arnold Schwarzenneger movie.
I hope you have a great time; Universal is fantastic!