I think Leah you wanted input on the book club and the book exchange. Me personally, I would do the book club, but not the exchange. I just can't guarantee that I would be reading books in a good time to then pass them on. (I'd end up getting it, not reading it and then sending it back out due to sheer guilt.) With a book club, there's no one depending on me. I can just participant as and when it's a good time for me to do so.
(I've just gotten myself involved with the local neighborhood newsletter...my first meeting and I have been elected to do all the typesetting and layout; the person doing it for the last five years just up and quit! This time obligation has me rather freaked now so I'm being more cautious than usual until I can see where this thing is heading.)