2001: A Space Odyssey - From the StarGate to the Star Child looking down on Earth, an amazing end to an astounding film.
Soylent Green: So that's where Soylent Green comes from....
Star Wars: As if the escape from the Death Star wasn't enough, there's an extended space battle between spaceships and a planet-sized Death Star. An award ceremony tops off the movie like a cherry on an ice cream Sundae. Perfect!
Close Encounters of the Third Kind: From the moment the Mothership appears over Devil's Tower to the climax when Neary is singled out from all the trained scientists to be travel with the aliens into outer space. This movie has remained a favorite of mine for those final twenty minutes.