what works are we "supposed to like" in the Less Wrong community?

Primarily HP:MoR and anime. And anything else, but only if we can find something interesting to say about it from a rationalist point of view. As grouchymusicologist says of the Grosse Fuge, gushing adulation on its own, even of HP:MoR, will not earn LessWrong points.

Agreed about GEB. It appears that the more someone already knows about mathematical logic, the less highly they rate GEB, to the point of weary eye-rolling from professionals in the field.