Jurassic Park is quite possibly Steven Spielberg's best film, and one of my favorite movies in general. Although the movie isn't too scary for older kids: there are two very intense scenes: when the T-Rex attacks the kids in the Jeep and playing hide and seek with raptors in a dark kitchen.
I loved this movie, and what CSM said about Jaws being better was total crap. Jaws was good, but didn't craft suspense as well, and I personally don't remember the characters in Jaws, so they obviously weren't very memorable. Anyways, Jurassic Park is a great movie and I highly recommend it.