The debate on Newsnight can be seen here and starts at 26:05.
Of course visualisation of data should aid communication, but for me, McCandless advocates the pretty picture road to infographics to the point where we can't tell what the main idea of the graphic is and needs further voice off explanation! I'm happy to report Brody was skeptical of the sorts of graphics McCandless creates and furthermore managed to plug his Anti-Design festival on 18-26.09.10. Something McCandless will no doubt find very unpretty.