Social Network is what I would consider his best work. When it comes to the technical aspects; direction, cinematography and screenplay are fantastic and the best he is ever done IMO. However im a bit partial torwards Se7en and Fight Club, which I would consider my personal favorites if for no other reason than nostalgia.
I'm in a pretty similar boat as you, though I'd put Gone Girl and Dragon Tattoo in the upper middle.
Need to get around to watching Panic Room and rewatching The Game some time...