I picked green... because I like green... on a more realistic note I'm not really sure. I seem to ask out blondes more... but I've asked out brunettes before. I tend to like girls for their personality more than their looks.
This is just me, but I hate non-natural hair colors. I prefer the natural brunette, blonde, and so on. The bright reds and purples and everything is just too much. I don't think a rainbow on your head looks good. Lol. However, if someone has black hair and puts a neon green highlight in it, I like that. I just do not prefer the entire head neon green.