A lot of people are gonna say Blizzard, but currently aside from the (enormous) WoW revenue, they don't really sell anything else.
Activision makes a whole lot of games, most notably the Call of Duty franchise, which I think makes them more money than WoW. Add Guitar Hero and all their other big franchises, and I personally think Activision makes more out of this deal.
Anyone with any numbers out there to compare?







