While looking over this question, it occurred to me that not every one would have heard of the famous "Bitcoin pizza" event, and so I suggested to @David Perry to add a link "to build up the Bitcoin Canon". I'm following the general idea that Canon is the formative material that shapes a given subject. Wikipedia has an example of Western Culture Canon that illustrates the kind of content that qualifies.
Since we are expecting this site to become one of the definitive resources about Bitcoin, it might help future researchers looking over old posts to be able to identify, or subsequently tag, significant Bitcoin moments and references with a "bitcoin-canon" tag.
Maybe it's all a bit above our station, but I thought I'd put it forward for discussion.