I just reread this book for probably the 4th time. These are probably two of my favorite characters in any book I've read in a long time. There will never be enough sequels or short story spin-offs to satisfy me. I will probably never tire of Luke and Nora.
edit: Just finished rereading the newly revised edition from Ylva Publishing. Me and Cheri did a co-review of it if you want to check it out at C-Spot Reviews