Easy. Fire Emblem.
Radiant Dawn is one of my favorite games of all time, Path of Radiance is really high too. I preordered Awakening and bought the 3DS (limited edition) only for this game. Biggest disappointment ever, the casual/dating sim turn the series took killed it for me. It barely even deserves the "TRPG" name now, and let's not talk about the economical model...