The list of books is good, but if you're only playing NL the Low Limit/Small Stakes book only cover limit play. The Theory of Poker is the classic but the use of other games in the examples I found a little distracting. If you get Sklansky's hold 'em books just about all of information in The Theory of Poker is embedded in them.

I'd also recommend investing in one of the serious poker simulators, either Turbo Texas Hold 'Em or Poker Academy Pro, so you can experiment with the various scenarios discussed in the book and burn the principles into your neural circuitry. Right now I'm more in favor of Poker Academy for that purpose since you can stack the deck and player hands and freeze the button in Poker Academy NL but not in Turbo Texas NL. On other hand, Poker Academy doesn't have an autotesting capability, but then again only the limit version of Turbo Texas has one. If your a Mac user then it will have to be Poker Academy.