We buy the Unofficial Guide every year, but I also have enjoyed The Complete Walt Disney World by Julie & Mike Neal. Full of beautiful color photos. Of course it makes me want to go right now!
Hmmm......I just checked my "member page" and the 30% discount code is still there......unless they've changed things after I joined. I think on the main page they offer 20%, but the larger discount if for those who choose to join their "community". And media mail has never taken 3 weeks when I've used it.....but that's just my experience.
Hands down for us is the "Unofficial Guide to Walt Disney World". The latest edition ( 2008) will begin deliveries from Amazon on Aug 23rd. It's an excellent guide.