The Houses are canon.
... I've known that for more than a decade. Reread my first comment; maybe the phrasing was unclear, although it doesn't seem unclear to me.
(I know that HPMoR attracts many non-HP-fans into reading it, but... seriously, is there really anyone out there who believes that the friggin' Hogwarts Houses made their first appearance into Yudkowsky's fanfic?!)
A while back in the Columbus Rationality group, we started wondering: What books would the Harry Potter and the Methods of Rationality houses have in each of their libraries? We had fun categorizing different subjects:
And so, I found myself taking all my books off their shelves this weekend and picking the best to represent each rationality!House and made them into Facebook cover-image-sized pictures. Click each image to see it larger, with a list on the left:
(first posted at Measure of Doubt)
I’m always open to book recommendations and suggestions for good fits. What other books would be especially appropriate for each shelf?