Supreme Commander (PC)
PC gamers have access to a lot of hardcore games - with so many shooters, strategy games and role players available for the platform, it's hard to pick a definitive title for this list. Retrobot thinks Supreme Commander is the game for this role. Coming from Chris Taylor, who brought the world the first fully 3D RTS with Total Annihilation in 1997, this RTS is a wholly consuming experience.
With thousands of units at your disposal, it's pretty clear you need a decent PC to run the game properly - a hazard of the hardcore gamer's favorite occupation. The best hardware configuration, running the best games will give the best experience, so you'd better be prepared to fork out. And Supreme Commander is the perfect game to test your new set-up with.
The game itself lets you stockpile commands for each unit (or group of), so you can set up an entire assault in advance before deploying it at just the right momemnt. Pull the camera up and away and you can even see the whole map as... well, a map - taking in the entire battlefield before zooming back in, seamlessly. An RTS with near incredible scope in more ways than one.