Serenity
There’s a good review of Serenity on Reason.com. (Spoilerific.)
I don’t follow many of the references present in that review, but I think I get the idea, and I’ll summarize it: Serenity is, in every sense of the word, Sci-Fi. Much of what we call Sci-Fi in the modern genre misses many of the older, classic Sci-Fi meanings. I think Serenity is a well executed reminder that Sci-Fi is more than just “guns in space”.