Um, second post.
2) A Partner (who has beacon practiced)
All the gear and internet reading in the world won't save you if you don't have BOTH of these. I consider these two to be the most important requirements for BC. Everything else is just stuff to help make the experience more enjoyable.
I'd say good knowledge and experience relating to snowpack analysis is most important requirement, but that's just my take. Better not to have to use the beacon IMO.