Elon Musk - SpaceX and Tesla have been on HN pretty consistently this year, and it's an inspiring option, too.
Snowden is not a bad choice, especially since he'll probably be snubbed by the Times in favor of the politically safe Miley Cyrus, but he's not really in tech. Satoshi Nakamoto should have been the HN POY last year (or next year once BTC goes really mainstream).