In no particular order, and make of ‘em what you will, people:
According to Wikipedia, 7 to 10% of the population is lefthanded. Apparently there’s something even more special about PunkAssReaders than we already suspected, because 14% of you are lefthanded, with another 5% being ambidextrous. I read somewhere once that lefties have a higher rate of accidental demise, the world unfortunately not being designed to accomodate their preferred spatial orientation, so take care!
Of the 11% of you who chose “None of the above” when asked what part of your body you washed first, over half of those can’t follow directions. The question specifically excluded hair, face and head, folks–back to grade school for each and every one of you! The rest apparently do not consider their armpits to be either a part of their arm or a part of their torso, but separate entities in of themselves, and either didn’t feel like specifying which side they start on or simultaneously scrub both pits from the get-go, which presents me with an interesting mental image. One of you does, indeed, start on the left armpit specifically though.
77% of our PunkAssReaders are of the lady gender, which is probably all Quin’s fault.
And yes, it is all as that unknown guy on the radio said and much to the ex-spouse’s chagrin–coming in at the big 37%, more of you start on the left arm or shoulder in the shower than anyplace else. The two next-most-common initial scrub locations are the chests or breasts (13%) and the torso or belly (11%). A whopping 6% of you do represent! for starting on the genitals. However, absolutely nobody wants to go anywhere near the butt to start off with (0%). One flexible and nonconformist individual starts with his or her back, which does actually impress me. The remainder divvy it up between neck, right arm or shoulder, or one leg or the other first.
More polls may be forthcoming at random intervals–stay tuned! 
If I was interested in maximizing efficiency, I would shampoo first, and let the shampoo do a little extra cleaning as it runs down. But I soap first, shampoo last, because…well mainly tradition at this point!
I start with my feet (usually the right foot first), because it is easier to wash them before starting the shower head.
Ambidextrous PAB readers, represent!
Well, I missed the survey, but chalk up another southpaw reader.
I’m also a southpaw, and was thinking of this poll when I was in the shower the other morning. The washcloth, in my right hand, went to my left armpit first. (In the words of a famous movie character, “It does it by itself!”) Then up and over the shoulder, and then to other regions.