Jonathan said it right:
“I also wouldn’t say that space opera is firmly entrenched within the confines of the science fiction field. Rather, I’d say that space opera is the truest, purest form of science fiction and it rightly occupies the very center of the field. Space opera has given science fiction its greatest icons and many of its greatest stories.”
From Mind Meld – it’s worth read in full if you like space opera; they’re answering the question of how to keep space opera relevant.
Me, I say: who cares about relevant?! I like what Tobias Buckell says, too: “massive spaceships, planets with two suns, big dumb objects (the deathstar), giant space battles, plucky heroes and larger than life settings.” Yeh! Woohoo!
 I don’t even know who Buckell is, but now I might have to find out.