Quick summary: the paradox of choice suggests that offering more options discourages people from making any selection, and reduces their satisfaction with their ultimate choice when they do. The research that Tyler Cowen cites suggests that there is no significant effect.
Apparently paradox of choice is rarely a factor and may not even be real; Tyler just put this up on Marginal Revolution http://www.marginalrevolution.com/marginalrevolution/2009/11/the-paradox-of-choice-is-not-robust.html
Quick summary: the paradox of choice suggests that offering more options discourages people from making any selection, and reduces their satisfaction with their ultimate choice when they do. The research that Tyler Cowen cites suggests that there is no significant effect.