In my long time of lusting over brown 2D, I came to the following conclusions:
>white hair/blonde
Maybe it's overexposure, but don't care much. Muh contrast, feels kinda cheap/lazy at times. Though a more dusty, sandy blonde can complement dark skin incredibly well.
>black hair
Never underestimate the power of a consistent color palette. Black skin can make them look mysterious and aloof. Can work really well with a contrasting outfit, like a white dress.
>brown
Brown hair looks energetic, confident and is perfect for tomboys.
>green
Looks goofy, but not necessarily in a bad way. Can work really well for more exotic fantasy races or people.
>purple
There needs to be more of this. Looks very exotic, mysterious, incredibly sexy.
>red
A darker, stronger red is perfect amazonian-combo.