The preferred rooms are marked with a black arrowed line. I've heard that since this map was made Disney has added more rooms to preferred. We stayed standard last time and were in the 80's rooms 9218-9219 facing the 90's parking lot. It was pretty close to everything and quiet.
On our next trip in 2008, we've decided to do preferred instead. We have always done standard and we always end up looking at a parking lot that's far away from everything. It came out to only $94 extra dollars per room for the week. I requested 60's or 70's quiet, connecting rooms away from the pools. Wish me luck!!!