Though I love all the civilizations, I do occasionally have the urge to run the game with a reduced set of them. There's so much interesting flavor you can get by putting just a few of these weirdos into a game world instead of the whole mess of 14 (20 with Travelogue).
One of my favorites is: Old-Worlders, Logicians, Stardwellers. Old-Worlders become the default point-of-view characters, who have interactions primarily with the Logicians at first and the Stardwellers later on. The Logicians think so differently from the Old-Worlders that they might as well be aliens, and the Stardwellers look different enough to be aliens. There's a significant technological hierarchy here as well, with the lower utterly unable to comprehend the higher's tech.
Another one is: Masquerade, Union, Cargo Cults. It's a much more polarized universe, with each side trying to capture/convert the remaining cults and their planets. Any of these cultures' allies can be substituted as long as they have roughly equivalent tech - you could put in the Tao or Stardwellers for the Masquerade, or the Replicants for the Union. Things just get weirder when you do.
Any combinations that you like?





