I would be a the original folklore version of something like a troll, oni, tengu, ogre, or some shit. Indefinite lifespan, vast array of superpowers, a culture somehow built around fucking with (I daresay trolling) idyllic villages for your amusement, and of course a bunch of mortals who consider a giant tree-swinging wizard a good enough reason to leave offerings of neat free stuff on the outskirts of their villages if there's enough sitings in the area.
The only things I would conceivably have to worry about are things like armies of people trying to band against me and clever youths and/or anthropomorphic cats in the midst of an adventure who would out-trickster me and either kill me or steal my favorite shit. Armies I probably wouldn't have to worry about that much, considering how much power I'd have at my disposal, but killing enough of them to fight them off would probably leave a bad taste in humanity's mouth even if it was in self defense, and would drastically reduce the amount and quality of potential worshippers. Oh, and sunlight, I guess I shouldn't be a troll. Or an Ogre. Ogres eat people for some reason, so I guess that would only /attract/ armies and tricksy hoomans. And I guess Oni and Tengu seem to be Always Lawful Evil for no particular reason, so that would really spoil my plans of being a benevolent freelance-dictator prank god.
Maybe I'd be a Tanuki or something. That's all the benefits I wanted to be a troll for, even though not quite as godly in power. I'd probably spend most of my time shapeshifted into a human with some cronenberg latex taped over my tail, because I'd literally prefer to have a lumpy tumor on my back than look like a tail-wearing degenerate. The vast array of scrotal party tricks I'd also have sounds disgusting, but hey, might come in handy someday I don't fucking know.