Serenity. :evil:
Star Trek over Star Wars. Original and TNG way over the last three ST series (progressively downhill after TNG; I can never choose between the original and TNG because both had their strengths). That said, the first SW movie is a total classic space opera. ESB was also excellent. RJ was the harbinger of the last three which were largely drek (some good stuff in the very last one, but not enough). I did like the fight with the Emperor in RJ, and the first time around the Ewoks beating the Imperial Stormtroopers with logs and rocks was a riot, but really a much weaker movie than the first two.
Some of my favorite SF movies: 2001, 5th Element, Day the Earth Stood Still, Metropolis, Forbidden Planet, Matrix (but NOT the sequels), Dune (for all its flaws). Other great SF TV shows: Dr Who, The Prisoner, Babylon 5, Firefly, Farscape, Twilight Zone.