Interesting to see Fincher go back to Reznor. For what it's worth, my fandom of NiN began with the opening credits of Seven:
http://www.youtube.com/watch?v=SEZK7mJoPLY
I wasn't terribly interested in the Social Network when I heard the premise (despite the fact I love Fincher as a director) but it's really starting to sound like a film worth seeing.