I'm not at all sure I'd put these in the Top 5... but Sam and Adam's selections made me think of them.
From the discussion of Network and its prescience about the current state of TV news, my mind went to 1979's Albert Brooks film Real Life, which pretty much parodied the current reality TV infestation long before it came. It's the one where a film crew totally wires a family's homes and lives so that every facet of their lives could be caught on film. Truthfully, I haven't seen it in years, but it went on my Netflix queue to see whether it deserves another look. (I don't think it's in the caliber of Network, but thematically it tied in.)
Also, adding to the list of political satires, 1967's The President's Analyst, which stars James Coburn as psychiatrist to the Commander in Chief, who ends up in the midst of spy versus counterspy in the Cold War era and social change of the late 60's. I recall this one being mentioned by critics about 10-15 years ago, which is when I saw it on videotape.
--Ann