Since this is retro gaming, I've got to go with Microprose (Civilization, Colonization, X-Com games and more). But my love also goes to other developers that EA destroyed, in particular Maxis, Westwood Studios and Origin. Special shout-out to three more studios I had amazing memories with: New World Computing (Might and Magic), Sir-Tech (Wizardry) and Blue Byte (Settlers, Battle Isle, Albion).