Thanks for the recommendation! I was thinking of one reason I like fantasy of manners more than high fantasy (and thinking about it, quite a bit of Diane Wynne Jones' work can be put in that category). For one thing, the setting in the books is not nearly as nostalgic as high fantasy; the social mileu is as much an obstacle as anything else. For another, the ones I've read have a more immediate, modern feel to the setting.

So, I have some more things to check out...after the three books currently on my reading list.