Personally, I never liked Harry Potter's lore, while it is unique and interesting in it's own right, I found that too many elements in the story were disjointed with no clear "connection" between them. This allowed for a crazily complicated and continually interesting story, but had the side-effect of a messy and disorganized lore.
The problem - and also, I think, what makes it so successful - with Harry Potter's world building is that it's not really meant to be an intricate continuity. It's the same thing that makes fairy tales work: the world bends in accordance to what the story needs to say or do, rather than the story working within the realms of predetermined rules. It works because Harry Potter is wish-fulfillment fiction for its target demographic: there are enough blanks that they can be filled in with whatever the reader's imagination likes best, and that makes the story more personal. And if one should take it at face value, it works well enough that way, too.
Back onto the original topic: I'm shocked no one seems to have mentioned Lord of the Rings/The Silmarillion, still the singular foundation for High Fantasy As We Know It (tm)!