I love this question. I think about it often.
Honestly I would end up a power-mad dictator bent on world domination. Once I achieved power I would be wanting more and more, until I probably ended up with so much I didn't know what to do with it. Then I'd probably search for immortality out of my fear of death, so I can keep my iron grip on the population of earth. I would use anything to gain immortality. I would sacrifice human souls to add their life span on to mine, Get infected by vampires, Turn myself into robot and just constantly upgrade me, or I might unlock the secret of the actual animal...the immortal jelly fish. (LOOK IT UP. IT's Stellar Awesome) Once I achieved immortality I would eventually be able to span my empire across the cosmos picking off alien races one by one until the entire universe was under my dominion. Soon after I would build up enough power to create life and they would worship me as a god. Then I would be content.
Granted that's the plan if everything goes perfect for me.