Friggin’ Jupiter.
It has a storm three times as big as earth that has existed for at least 300 years.
The planet’s weather phenomena are so complex that they almost resemble huge-sized life forms.
Jupiter’s “surface” is an ocean of liquid metal.
Jupiter spins so fast (once every eight hours) that it bulges out noticeably in its center. Like all planets, the spinning makes it act as an electromagnetic dynamo; but Jupiter’s magnetic field is so huge and powerful that it nearly reaches Earth; it also screws up electronic devices that fly close to it.
If Jupiter was any bigger, its gravity would cause enough pressure to generate fusion and it would be a star.
Jupiter’s moons are also pretty rad. Io ejects so much volcanic debris that it creates a “donut” around Jupiter’s magnetosphere. Europa might have an ocean of life-bearing water underneath its icy crust.
Saturn is also pretty awesome.