But it's a mistake to think that these places have a monopoly on ideas or are stepping stones to great things in this business. A lot of Ivy Plus types get admitted to Harvard or Stanford on the basis of strong standardized test scores, which are not a good indicator of creativity. I know of a late '90s Harvard College CS grad who hasn't done anything remarkable with software development or Web technologies. An MIT grad I briefly worked with had some interesting insights, but many of her ideas came from other people.
It's also important to recognize that someone with skills and a great idea can develop very special technologies no matter where they are studying CS -- or even if they are not formally studying anything. Shaun Fanning didn't come up with Napster at Harvard, he developed it at his dorm room at Northeastern. Jaron Lanier (the guy who coined the term "virtual reality" and developed many early applications) was a student researcher at New Mexico State University before heading off to the Valley.
Bottom line: Seek out those schools with great faculty and programs that interest you, but remembver that success depends on the ideas bouncing around your head, not the name of the university on your resume.