One thing to consider in choosing a bike color:

In some communities (my daughter's college, for instance) old beater bikes are aquired, put into working order, spray painted yellow and put out for use by anyone to ride. In those communities owning a bike that just happens to be yellow would be hazardous.

I really like the YellowBike idea, but I'm never going to buy a yellow bike for that reason. That and the fact my bikes are blue, darn it.