Apple or XBL but assuming it must be a retail game: Nintendo.
Reason is pretty cynical: I could buy the rights to some old classic platformer: Say Earthworm Jim, Bonk or Vectorman - hire some old-school talent and let them go wild with making a fantastic but focused platformer.
Do some targeted marketing to those old enough to remember the classic games and if I get 100,000+ sales, I've made a profit.
If we can pretend cost/profit factors don't exist, I'd make an updated Freedom Force for Wii/WiiU/3DS with online multiplayer on WiiU/3DS and local multiplayer on Wii/WiiU







