I'm also more of a Communist in terms of Civilization III (my true political ideology couldn't be farther away, however).
Main reasons are basically the extremely low corruption rates which help alot when you have empires as big as I usually (meaning always) do, and the fact that communism is a militaristic government, meaning war and its effects are no problem but rather an enticing political decision when your empire needs some boosting in terms of economy, technology, and rating.
I'd play as a fascist state more often if the effects of xenophobia weren't so dramatic. I mean, fascist states shouldn't recieve negative effects from xenophobia in the form that they do in Civ but rather a boost of some sort to represent the industriousness that is sparked in the indegeneous people of your country by xenophobia (e.g. fear of outsourcing and therefore an innitiative to work more effeciently).