Linus Torvalds. He created Linux and Git, both used by millions of people. He started to create Linux when he was 21 and still in university. It is currently running on a lot of devices including Android. That is really an accomplishment, to make an operating system is one of the most complex things you can create as a programmer. It is also cool that it's open source and how it is maintained. Both Linux and Git was created because he needed them, he creates things that are useful. He could have earned a lot of money but he cares much more about tools and software than money. I think he is a great person and speaker (and he is from my neighboring country Finland 🙂). I use Git everyday in my work and it makes it so much easier. He is for me without a doubt the best programmer in the world.