I'm not reading as I don't have the books anymore; however, I'll be happy to comment/discuss the points others bring up.
Very much so. In fact, I think this quality pervades most all of the book. One of the strongest aspects of the series is how The Dark, the unseen/unknown in general, the ancient mystery, etc. are constantly implied through the writing. You rarely have characters battling the evil forces face-to-face ala Harry Potter or Lord of the Rings; instead you have the characters living relatively normal, quiet lives in which the magical "otherness" invades in very subtle ways. I also love how subtly the series (and TDIR probably does this more than any of the others) slips between time and places so that we get a sense of reality in the series being this multi-layered thing, rather than having the "separate" worlds of, say, Hogwarts and Muggles.