I am wishing the choices for custom race colours were more sophisticated. Playing as the mighty Space Canadians means that if there's Drengi on my map, they get my red. I can't change their colour, and if I pick anything reddish, it can get confusing, especially on the top of the minimap where there's that "shine", or on the graphs. The default races have picked for them the colours that I would have liked to use myself.
What custom colour do you use for your civ? I have settled for a kind of unpleasant salmon orange, but it reminds me of the episode of the Simpsons where Homer goes to work in the pink shirt and gets thrown into an insane asylum as a result. It would be nice to be able to edit the other civ's colours, and to be able to change colours on the fly in the game, and not just on the set-up screen.