Anyway, OP:
Give or take what you want to concentrate on (tourneys vs. cash), a basic core of NLHE books would be something like:
LGB and Theory of Poker (which is not NLHE specific) are fine, so are Harrington's books. PNL and SNG Strat are a little more advanced but all are within the grasp of a reasonably intelligent person, which you should certainly be if you're taking up studying poker anyway. There are a few others you could consider like Largay's book or LBB, and then there are the Harrington on Cash volumes, PNL2, and the expanded TPFAP coming out pretty soon.
Ray Zee was just pointing out in another thread that if you can't absorb advanced material, you're not going to be a winner at any stakes that matter in any case.
As far as Super System, Doyle's cash chapter is essentially the same in both volumes. It's also somewhat dated, although the key concepts like aggression are still important, obviously. I'd recommend volume 2 for all of the vastly improved other chapters, however Chip Reese's stud7 in the first volume is still the highlight of both books IMO.
EDIT: Super System 2 is online to read free, maybe if you look around SS1 is there somewhere too
http://www.doylespokerroom.com/poker/poker_online.cfm