I stumbled across Eric S Raymond's Glossary of SF Jargon on friday and it's a pretty fun read. [index] And he's got a long essay on the whole subject. The most interesting part to me was the Federation model towards the end.

So what will I pick for my SF world?
- ansible and NAFAL (pretty much exactly like LeGuin and Card)
- biogenetic alteration
- no AI (I don't believe in it)
- probably pretty far in the future to give some time for interesting development
- no aliens (don't believe in that, either. like Herbert.)
- near term rise of corporations (esp. health care, which is already rising, like in Sterling's Holy Fire) and distributed nations and bioegineering and cybernetics and growing gap between rich and poor and angels (rich people who flee to zero-g) and development of the Internet (like Gibson and Stephenson). not sure about nanotech, but i like it's role in those guys' books.