For me, it's Futurama, because it embodies everything that The Simpsons was in its early seasons and what it is today. To me, the most memorable Simpsons episodes are the ones that focus on the development of one or two characters (eg: "Bart Gets an F", "Homer the Smithers"). The show hasn't had that for years, instead focusing more on zany antics. But Futurama manages to have crazy, insane adventures, while still retaining some fantastic (and sometimes emotional) character moments (eg: "Jurassic Bark", "Lethal Inspection", "The Late Philip J. Fry")