Honestly after seeing all the hype about heroes of the storm a few weeks ago, I am optimistically looking forward to the three Heroes of the Storm panels. Since I'm obligated to pick one, I think the best will be Heroes of the Storm Live Matches; getting a chance to see some live action gameplay well before release just sounds incredible.
I am looking forward to watching all of the panels I can. I am mainly a WoW player which means the one that is truly interesting is the World of Warcraft: What's Next. I kind of want to see how the "movie" is going along because that would be interesting to see how it is adapted on the big screen, whether it will be current WoW lore or whether or not it will be in the Warcraft III area.