I can venture forth some thoughts and a partial answer. I can't find info specific to North America; I found some pertaining to the U.S. and some that span the world. About a dozen years ago, I read a study that said blue is Americans' favorite color, followed by green and then red, I believe. (I can no longer find that study; sorry.) Since then, I have found that blue remains supreme to all Americans of all racial and ethnic groups. As for the least favorite colors, it depends on the context *as well as* whom you ask. According to one study, yellow seems to be the least well liked hue. However, further down the page, the author mentions the almost universal hatred of pink (1). Orange seems to be the next least liked color, although young Americans tend to like it.
According to a worldwide study, blue is the world's fave color and white is the world's least favorite (except in Mexico, China, and Brazil) (2).
Sorry I can't find the exact answer to this, but I think you're safe choosing pink, orange, or white to represent North Americans' least fave color.
(1) http://books.google.com/books?id=hoRooqUJwVsC&pg=PA52&lpg=PA52&dq=americans%27+least+favorite+color&source=bl&ots=uBdAkQk_TB&sig=e-WYY8wKCcwiTKL-DkSgj1dhGW0&hl=en&ei=dUmwSr2ODomasgOn6r3ACw&sa=X&oi=book_result&ct=result&resnum=3#v=onepage&q=americans%27%20least%20favorite%20color&f=false
(2) http://webcenters.netscape.compuserve.com/homerealestate/package.jsp?name=fte/popularcolor/popularcolor
Her favorite color was brown. At least it was in clothing.
Justin Biebers least favorite color is yellow.
Brown
Clear
red
her absolute fav colour is bright neon green, and i think her least fav colour is pink i think
his least Favorite color is grey he thinks it is too cloudy and dull
Purple :)
depends on the person
Pink
Your least favorite color!
blue