| This debate is probably only of import to pedants like myself, but I always wince when I hear someone call Star Wars "great science fiction."
I wince because there's really no science in Star Wars. It's great space opera sure, which is a subset of the broad domain called science fiction. It also chaps my buttocks when people talk about great science fiction on TV. With the possible exception of B5, I can't think of a single great science fiction show on television in the last decade.
(And I know fans of Farscape and Firefly and a few other shows will take me to task on this -- but I remain steadfast in my refusal to accept glossed-over technology and the impact those technologies have on the human race as part and parcel of good science fiction.)
So the pedant in me likes to categorize things a little more specifically; the broad brush of "science fiction" is used far too liberally IMO. Farscape and Firefly would fit under "SciFi" in my mind. There has been almost nothing that fits under "SF" -- the category of fiction where hard science actually holds sway.
But enough gnashing of nit-picking teeth. The lead-in to my question was far longer than I expected, but I suppose I shouldn't be surprised. What I'd like to know is what "good science fiction" means to you? What do you look for in decent SF literature? And yes, use the broad-brush meaning of "science fiction." I know not everyone likes Forwardesque or Nivenesque or Pournellesque hard SF.
For myself, I always look for the fact that technologies are used in more than one application. You have a weapon the size of a handgun that can vaporize titanium? Then your society has fabulous miniaturization technology, remarkable power technology and (unsurprisingly) scary military tech. How does that affect the rest of society? You have a FTL drive? Great! That affects interplanetary and interstellar communications, trade, colonization, and the occupants will suffer from the effects of time dilation -- 2 years subjective time aboard ship may mean 40 years on the colonies.
I also really hate human[oid] aliens, particularly ones that we can readily comprehend. I understand why this device is used in movies and TV (so that the audience can relate to them), but in a good hard SF novel, they should be inscrutable and shockingly different. The aliens in Robert Forward's Dragon's Egg is an excellent example.
GAH. I should go to bed. Throat still feels like I'm swallowing broken glass. :-/ | 
