Stephanie - I am so jealous of all of you going in December! But a Dec. trip is just not in the cards for us this year. We ARE planning for Dec. 09.
missj1975 - Some of the sharks are not too bad. I did trade for a pin for DS with a man who specifically told me I was getting the short end of the stick, but I was OK with it. DS had the "scuba" hidden Mickey set from last year and the Goofy had some of the paint fall off. (It was kind of weird. Not sure how that happened.) I really wanted him to have another one so I traded a limited edition pin to get it for him. I knew it was an LE pin, and we bought them on clearance planning to trade them so I didn't care. The sharks I don't care for are the ones who tell you to go buy them 3 or 4 pins in the shop and they will give you ONE of their pins in trade. I have personally not ever had that happen, but I know it does happen from time to time.
The Guest Relations books are hit and miss. We have found some neat pins in them in the past.
I don't know that I really have a "favorite" pin from the trip. I was able to find the rest of the ones from the box set where each one has a little saying. My favorite is Ezra from Haunted Mansion with "Where everyone is dying to meet you." I found that at Epcot one morning waiting for the Soarin' rope to drop. DS found the Aladdin one for me so now I have all 10 different ones.
DH likes to look for unusual/rare pins. Sometimes he finds some neat ones! I haven't added his new ones to PinPics yet so I don't know what his best find was this time.
I think we traded close to 400 pins between all 3 of us. I think we brought close to 500 to trade, but we came home with traders left over.
We were REALLY disappointed in the pins at MGM. Even on the days we were there at rope drop it was obvious that none of the lanyards had been refreshed - it was basically a waste of time to look for pins in that park.
DS did get a cool "dream" when he traded with a Dream Squad guy at MGM one night. DS chose a pin that had a "magic" back, so he got to choose a ride to have a Fast Pass for. The Dream guy took us straight to ToT (which DS hated before this trip, but that was what he chose) and went through the Fast Pass queue with us. He told us all sorts of facts about the attraction and pointed out some little details in the theming. He was very nice! DS got a magical moment certificate, too.

DS and I both won the "magic pin" game last summer but we weren't sure if they were still doing it this year.