@Introverted_Leo and @willbrawn have the right of it—Firefly and Serenity are your best bets, I think. (And of course BSG.)
Sci-Fi can be hard to find because it’s difficult to pitch to the general public (I think).
Dollhouse is good, and has some sci-fi elements, but it’s a tv show.
Fringe is okay, but a lot of people have complained about the science, and, again, that’s a tv show.
I think The Prestige could be argued as Sci-Fi, especially given the time period it’s representing. (It’s also an intelligent movie!) Similarly, The Illusionist could also be argued as Sci-Fi, but it’s more of a romance than The Prestige. (I would say both are more Steampunk in their Sci-Fi.)