I thought about this so much I made a blog post about it. 👍 Here's the important parts:
WARNING: WALL OF TEXT ALERT!!!
Assuming I found out I could live forever right now, I would start off by staying in college until I’d taken every interesting class there was to take. After spending the next decades (or even centuries) playing in all the musical groups that I want to play in and becoming a better bass trombone/euphonium player all the time, I would have amassed a small fortune with which to start my own corporation, which I would strategically time and market with my business skills acquired in college, and overtime would amass a more massive fortune, which would allow me to build my own island country in the Pacific Ocean. A very large island, this country would be run full time by me (since I can live forever), would feature stunning beaches, majestic mountains, and a massive metropolis called Central City, which would become one of the premier cities of the world, right up there with New York City, Tokyo, Paris, and Beverage Town, Arkansas. It would serve as the United States’s ally and partner during wartime, with a naval base on the northern coast and an air base in the northern mountains. Both locations would serve as strategic refueling stations during a Pacific assault and the country would provide the United States with a first line of defense should anyone try to invade through the Pacific Ocean. The country’s own military would be fledgling at first but well equipped with the latest American technology, and would grow into a small (due to the country’s size) but very deadly force. The country would be the model nation in the world for economic stability, human rights and freedoms, technology, and now-uncommon sense. I would spend many decades and even centuries leading this nation, until I was sufficiently wealthy enough to take to the stars.
By this point space travel would be the norm, the Solar System would be colonized, and technology would be advancing ever faster. While still leading my country, in my spare time I would build my own spacecraft using the scientific skills learned in college combined with the latest impulse drives, hyperdrives, artificial gravity systems and electronics. As soon as the ship was complete, I would bid my country adieu and take to the stars. I would spend the next millenia mapping the entire Milky Way Galaxy, being sure to upgrade my ship whenever necessary. Once finished, I would settle down on a nice planet and begin my revamp of the Milky Way Galaxy. By this time the human race would have expanded into most of the galaxy, so I would pop into the nearest planet to collect all the latest tech. Then I would set to work building a star, a star so massive that once complete, I would somehow destroy the black hole in the middle of the galaxy and replace it with the star, and the rest of the galaxy would continue to turn around it and be affected by its gravity at the exact same level as they did with the black hole. This star would initially be used to create the loudest stereo system ever. What I would do is design a stereo that produces sound from inside the star, using the sun’s constant energy as its power source. With such a monster power source and speakers that spanned the entire surface of the star, I would then create the loudest music in the world using new gradual directional sound waves. These sound waves would make it possible for planets close to the star to hear sound out of the stereo just as loud as a planet at the very edge of the galaxy. What would I do with this stereo? Blast Pines of Rome so that the entire galaxy could hear it to signify the opening of the new central hub of the human race, a massive solar system revolving around the central star.
The star would be far too bright for anyone to see from any distance, so it would be covered by a nebula stretching across all of the planets orbiting the star. The central solar system would be the capital of the human race in every sense; five dead brown dwarf stars would orbit the central star, and each brown dwarf would have five planets orbiting it, each with five moons (because according to Galactic Civilizations II, moons boost a planet’s economic growth ). Each pod (consisting of a brown dwarf and its 5 satellites) would be the galactic capital of a certain aspect of human life; there would be a manufacturing pod, where each planet was devoted entirely to manufacturing, an economic pod, where each planet was devoted entirely to economic growth, a trade pod, with each planet serving as a massive trade hub, a research hub, where each planet was devoted entirely to scientific research, and a paradise hub, with five planets all being the highest quality planets in the galaxy and turned entirely into planets of paradise for people to vacation at.
But this would only satisfy me for a time, and once technology caught up to me (or I invented the technology), I would build a new spacecraft for myself; one of epic proportions. This spacecraft would be powered by prototypical warp drives enabling speedy intergalactic travel, a first for the human race. It would be massive, so large it could hold a medium-sized planet within its hull. This size would be for storage, engine rooms, huge scientific laboratories, and of course, the universe’s first fully-functioning and fully-featured holideck, which, like the first computers, would require a massive amount of space for all the programming code, even with processors being less than a micron across. This would be my last resort ship, a ship I would turn to at the day when I was bored with the entire universe and would retreat into the holideck forever.
But with this ship first I would explore other galaxies and map them out as well. I’d take one galaxy far away from civilization and claim it as my Galaxy of Research, which would basically involve me building a giant particle accelerator that accelerated stars instead of atoms, and using it to crash stars into each other for fun. In my spare time from colliding stars and making black holes and awesome stuff like that, I would create a corporation based out of my personal galaxy that would build and deliver custom-designed planets for wealthy clients. Planet delivery would require a state of the art fleet of massive planetary transport ships, which I would create in the center of the galaxy at the largest spaceport in the known universe. After many years of successful business as a planet builder, after researching the appropriate technologies I would be able to create star nurseries for creating stars, and would induce agents that would drastically speed up the process, to the point where a new star could be created in a period of a few weeks. Further research would later allow me to govern every property of every star that was made, which would allow me to offer custom stars for the wealthiest clients, which could also be delivered. Add this to the planetary construction and prototypical black hole creation offerings, and I would be able to offer complete galaxies to clients, as prefab schematics or completely custom. In addition to creating playthings for the rich and famous and tailored galaxies for major corporations to set up HQ in, I would also perform public service to the human race and the universe by populating it with additional galaxies, especially when by now we would have expanded to many different galaxies.
Eventually, we would arrive at the point where every family doesn’t have a house, it has a planet. The solar system would be the street you live on, and the arm of the galaxy would be your neighborhood. The planets families would live in would largely be self-rejuvenating, meaning the planet wouldn’t have to be cared for in any way, it would just replenish itself in a regular cycle. It would reach the point where instead of kids riding their bikes over to their friends’ houses, they would pilot their little spaceships to their friends’ planets. With planets the new homes, solar systems the new streets, galactic arms the new neighborhoods and galaxies the new countries, my corporation would become like the home building and neighborhood designing contractors of today, which would make it more profitable than ever. Custom galaxies wouldn’t just go to the rich and famous, they’d go to corporations, groups of people who wanted to set up their own country, and more. Instead of owning a mansion, a rich person or family would buy out a solar system. Instead of video games, we’d have holidecks, and eventually holidecks would mimick the progress of the computer and we’d go from one holideck being the size of a planet and having very limited availability due to public use to having our own personal holidecks which we could take with us and activate on the go. Transgalactic flights would be the new trans-Atlantic flights, and every spaceplane would feature holidecks instead of TVs in every screen. Life would be broadly similar to today, just on a much vaster scale.
TL;DR: I would be awesome.
and travel the world!
But how would I end it 
