Warcraft. I used to play Warcraft III on my Dad's PC years ago, and it makes me sad that it's been dropped since the release of World of Warcraft (which I can't get into...)
Considering what Blizzard said at Gamescom 2015, perhaps you'll get your wish in the years to come. They've said Warcraft hasn't been written off and they'll consider going back to it after they're done with StarCraft 2.
Command & Conquer along with Warhammer 40k: Dawn of War for me.