Right now I"m leaning towards Gravitonics (for the capacity bonuses) and Slavers (for the Slave building abilities).
Are there any other particularly good choices for a civilization that people would recommend?
Synthetic and Slavers?
With a Synthetic Civilization thouugh, it's less useful as the Slaver bonuses mostly favor morale and +1 pop cap increase (already 100 anyways).
One feedback to Stardock might be to make "Synthetic" bonus for Slavers only.