Just thought I should bring up some random season 2 facts I'm thinking up:
-so far, out of the 15 shown episodes this season, Jack is the only one to have 2 'centric' episodes (Jack, Michael, Locke, Hurley, Jin/Sun, Shannon, Tailies, Ana-Lucia, Kate, Eko, Jack, Charlie, Sawyer, Sayid, Claire) this season. This will most likely change before the end of the season.
-this season, a total of 16 people have appeared in the opening credits, although not all at the same time (the 13 survivoring cast members from season 1, AL, Eko and Libby).
-Jack's second 'centric' episode of both seasons have both been the 11th episodes of each respective season.
I'll probably figure some more out later.