"The Morris worm or Internet worm was one of the first computer worms distributed via the Internet; it is considered the first worm and was certainly the first to gain significant mainstream media attention. It was written by a student at Cornell University, Robert Tappan Morris, and launched on November 2, 1988 from MIT. The worm was released from MIT to disguise the fact that the worm originally came from Cornell. (Incidentally, Robert Tappan Morris is now an associate professor at MIT.)"

What I liked about the morris worm was that it exploited multiple operating systems (VAX and sun), caused the creation of CERT, and utilized multiple vulnerabilities to spread making it truely ahead of its time.

Morris Worm Link: http://en.wikipedia.org/wiki/Morris_worm