Although I don't think this is Spielberg's best film (that would be probably be Jaws, Raiders or Schindler's List) in many ways it's my favourite. I still have fond memories of going to see this over and over again during the summer of 93. Nothing topped that first viewing, though.
Unlike movies now days, the trailers barely hinted at what was in the film and just showed quick glimpses of the animatronic dinosaurs. So when I finally saw the film I was literally gobsmacked. CGI has been refined since, but I'd argue it's never been used as effectively as those six minutes in Jurassic Park. The sight of the dinosaurs still has what has been lacking in nearly every film since - genuine awe.
Of course many people complained that the humans in the film were boring compared to the dinosaurs, but so what. The characters were even more cardboard in the book and at least the actors in the film were likable. Like Jaws and Star Wars, JP ushered in a new era of filmmaking. Unfortunately, most of the big effects films since haven't understood the less is more approach is the more effective one.