No way to decide ... Farscape had such a cool ship, and a really cool plot line ... + Great Characters (esp. Pilot) and Great Effects.
I really liked Firefly .. but it limped in places in the TV show ... which made me feel bad for it. On the other hand it was very, very relevant to the scene today .. and creative in ways other shows lack.
I have always favored Star Trek because it was totally multi-ethnic .. and it explored lots and lots of perspectives. It was always very professional, (after Cowboy Kirk retired).