Most Helpful Guy
On me or the one I'm humping? Platinum blonde is my favorite (the natural type, not the bleached crap that's making her have roots and/or slowly go bald). Red second. Brown/Auburn 3rd. Brunette last. This is assuming all else equal. Hair is the first thing I notice but isn't everything.
Most Helpful Girl
I like my hair been ginger for now. I've had all the colours you've mentioned. My favourites were red, purple, blue and ginger