I picked Torn Asunder, though most of the books have been very good.
I think Steve, Kevin, and the rest of BP did an excellent job on TA, and I have even used it on occassion in my games (It is a rarity for me to use any published book besides the WoTC core books and a few select others).
I also really liked Oathbound and the equipment book.
Keep up the good work!
See ya,
Ken Shannon