Star Wars, or Star Trek...
I can't believe I've never blogged this one. It's one of the biggest geek jihads there is.
Well... it really depends on what you consider canon. How much of the "universe" of each you allow into your evaluation.
If we go just on the movies and TV shows, Star Trek by a country mile... even with the soft and squishy pseudosocialism crap.
The writing, the acting, the cinematography, and the direction of Star Trek are in general far superior to Star Wars; as is the general body of work (one great, one good, two bad, one mediocre and two AWFUL movies, and one good and one bad TV show on the Star Wars side. Three great, three good, three bad and two AWFUL movies, and three good, one mediocre, and two bad TV shows for Star Trek).
As SciFi as a whole... that's more difficult. Star Trek is really post golden age science fiction, whereas Star Wars is classic golden age Space Opera. They're really different genres, and are difficult to compare directly.
If we include the full universe of each, including the novels and in canon video games... It's a wash. Two entirely different philosophies, two entirely different universes, two entirely different sets of writing styles etc... and lots of great writers/authors for both (witness Mike Stackpole, and Vonda McIntyre).
My general personal preference is for Star Trek; because I like the characters and character oriented writing, more than the archetypal mythological arc oriented writing of the Star Wars franchise.
