Get all the volumes of Harrington On Hold"em.
Others I would suggest since you alread have both Super Systems are Small Stakes Hold"em (Sklansky and Miller); Theory of Poker (Sklansky); Sit n' Go Strategy (Collin Moshman): and just a good read not related to strategy is Positively Fifth Street (Jim McManus)
Also get a subscription to Card Player, it comes out every two weeks and there are some great articles in it, much more in depth than either Bluff or All In.
There's also lots of really good books for Stud and Omaha, although not nearly as many as there are for NLH. There's also a lot of just plain crap out there, stuff that was published just to capitalize on the popularity of Hold'em.