I found both really interesting. Whereas the xkcd article (http://blog.xkcd.com/2010/05/03/color-survey-results/) goes into some detail into one experiment, the original article has a wider scope and touches on several experiments, the xkcd experiment being one of them.

Also interesting is the follow-up article about how language is used by the brain to distinguish between different colours (http://www.empiricalzeal.com/2012/06/11/the-crayola-fication...).