I've been amusing myself all day with doing some complex plotting in Sage. The default color scheme has 0=black, infinity=white, and red=real. A lot of the time, this doesn't work too well, but if you plot f/abs(f) the color will just depend on the complex argument. For example, if f = (z^5+1)/(z^5-1) we get:

Or a more baroque example, f = z*log(z)*exp((z^5+1)/(z^5-1)^(1/2)):

Sometimes the default coloring is helpful, for example when showing the essential singularity at 0 of exp(1/z):