Abhorsen

Abhorsen is the second half of the story begun in Lirael.  I didn't like Lirael as much as I liked Sabriel, feeling that Nix spends too much time on his two protagonists' doing that teenager thing of "nobody understands me; I'm different to everyone else; etc".  In Abhorsen, Nix is back in fine form.

One thing I loved about Lirael was the lyrical writing.  In Abhorsen, Nix has Lirael go on a long journey through the lands of death, and I felt that his description of the journey was very effective; the nine areas that Lirael travels through feel disparate, yet unified.  Her showdown with Hedge in the last of these didn't come down to a test of strength, which would have felt silly, but instead grew out of the way Death has been presented to us over the course of the books.

As a side note, I thought it was pretty clear that the Destroyer, the main bad guy of the series, is actually a personification of an atomic bomb.  It's housed in two metal hemispheres that set off a chain reaction when brought together, starting with a pillar of fire.