I'd vote for the pax prime panel, with the what is firewatch stuff and the amazing ending.
Also the first game and other stuff from the halloween unprofessional friday http://www.giantbomb.com/videos/unprofessional-fridays-10-31-2014/2300-9648/
Also every venture into the Boobah zone. And a ton of the extra life stuff, but especially gamebutts.
And lest we forget Barkerville happened this year.