Ask HN: What are the 10-12 most important conferences each year?

Which conferences are the ones where truly historic decisions are made? Where you can meet people who will inspire? Where you'll find youself at talks that you already can't wait to go home and watch again? Where the random party conversations end up turning into household-name projects?

Note: I don't necessarily mean big conferences, although those are fine too. I also want to hear about some small ones that you think are great.