Mercury Rising, Billion Dollar Brain, Hot Millions, Net Force, Simone, Virtuosity, Enigma, Colossus: The Forbidden Project, The Computer Wore Tennis Shoes, Explorers, Short Circuit 1,2,3, The Thirteenth Floor, Electric Dream, Logan's Run.
A small collection I can remember off the top of my head, there are loads more I would class as 'geek' movies though.