Hmm,isn't it Pax Prime that had 70,000 people?
http://www.joystiq.com/2012/04/19/pax-east-er-largest-show-to-date-no-more-pax-attendance-figure/
edit: Pax East 69,500
http://www.joystiq.com/2011/03/14/pax-east-2011-attendance-69-500-officially-becomes-biggest-pax/