Hair colour doesn't generally figure into my preferences. I like all colours, but the length generally comes into play, the longer the better.
I've had the one experience with a Red Head. Fiery. She was Scottish, and a Sagittarius. She had curly hair down to her bum, and being a horny virgin it was love at first sight.
6 months after meeting her she shaved her head and then locked my balls in her side table. I was still horny as so I stuck around, but it was devastating to see all that lovely hair disappear overnight.
Unless you are a masochist, stay away from the red headed Scottish lasses who are born under the Sagi sign.