[adam]

I think it's more a stylistic issue than a thematic issue, myrrh. I mean, I think what you're saying is broadly applicable to any genre; take comedy movies, for instance. You could find some comedy movies from the 70s that seem really dated today and really mired in specific 70s sensibilities, and you could find some that (almost) could have come out yesterday. I don't think it has much to do with the theme...I think a good story could be written about an inter-species federation, but that most of them we've been exposed to are simplistic and/or campy (Star Trek). Science fiction that hasn't dated itself: Dune, as mentioned, Carl Sagan's Contact (fantastic book), William Gibson's Neuromancer (just finished it, was impressed with how current it seemed considering it's 20 years old).

It also, obviously, really depends on their approach to technology. I mean, one thing that makes Star Trek seem dated is that their computers look like light bright sets, and why the hell does Spock have to peer into that little window like that?