Well, I make a Bet with WoW. And we have all those Blizzard games, last time I heard Diablo II sold 20 million. Warcraft,WoW,Diablo,StarCraft and some other I can't remember are so high, Blizzard make a few games, but the few they make are all Legendary in matter of quality and profit.
Blizzard should be the company that have most profit per title.