Best game ever: UFO - Enemy Unknown - the 90's original, before it went all flashy graphics. It was the perfect blend of base-building, research, turn-based squad stuff, economics, more turn-based squad stuff, and getting your entire team wiped out on the ramp down from your craft. Ah, those were the days, my friends. Those were the days. Recently I'd have to say Dragon Age (the first one), and Bethesda's single-player offerings of Skyrim/Fallout series.