What I packed:
Casual clothing -- shorts/pants, shirts/t-shirts, (long-sleeved shirts too), underwear, socks, pajamas
Sweatshirt (I packed sweatshirts for my sons, but couldn't help buying them fleece pullovers our first day. (It was chillly!) One had Mickey and Gang, the other had Buzz Lightyear. They were $25 each and they wore them every day -- my son never wanted to take his off.) Obviously, I didn't need to pack the sweatshirts.
Comfortable shoes
Swim suits / trunks (It was too cold while we were there, though there were a few brave souls in the pool while we were there.) The resort we stayed at (POFQ) had towels available.
Sun protection (sunscreen, hat)
Rain gear -- I didn't pack. It did rain the three days before we arrived. My plan was to pick up ponchos if we really needed to. They sell them in every store.)
Comfortable bag to carry items during the day. (Back pack, camera bag or waist pack. We had a diaper bag.)
Toiletries (brush/comb, toothbrush, toothpaste, shampoo/conditioner (I brought a scrunchie to pull my hair back. Didn't want to waste time w/hair dryer and curling iron on vacation), deodorant, make-up (DH brought his razor/shaving cream but I don't think he shaved once.)
Camera, film and extra battery. (My camera is a battery hog -- I guess I take too many pictures)
Money (Credit Card and Cash -- 5's and 1's for tipping)
Personal ID -- you can't get on a plane anymore without an ID
Prescription medicine (my youngest has excema -- poor thing.)
Tylenol -- Children's and Adult -- (Glad I packed it -- I had a headache on Day 2, 4 year-old needed it Day 3)
CORKSCREW (I didn't think to pack one -- housekeeping kindly brought one up to us.)
Cell phone
Nightlight (4 yr old is going through a phase. )
Snacks (I filled a large ziploc with small snacks for the kids, which I put in my checked luggage. Each day I would pack an assortment of snacks in my bag to take to the park, along with some fruit (and bottles for the baby). The snacks included goldfish, raisins, cheerios for the little one -- gummy worms and trail mix for my 4-year old. Oreos, Snackwells, chewy granola bars and a few clementines were in the mix too. The snacks I packed in my bag varied from day to day.)
-----
Resort reservation documents
Plane Tickets
Reservation info for plane and limo service (We had YourRide picking us up)
Park Hopper Passes
MVMCP tickets
Disney Club card
----
Backpack of toys/activities for 4-year old on plane (Play-doh, Disney coloring pages (that I found online), crayons, CD player and a CD of son's favorite songs.)
----
Stroller
Backpack carrier
Extra bag for purchases. (We threw the backpack carrier (my 15-month old strolled through Disney on DH's back) into an extra large duffle, which we checked on the plane. There was a lot of extra room for purchases. I did a little bit of Christmas shopping in DTD.
----
THAT'S IT! We went with 2 small bags (normally carry-on luggage), one large bag, and then the extra-large duffel that only had the carrier in it going down to Disney, and contained toys and gifts coming home.) Even as minimally as we packed, we STILL felt overpacked as we never wore the shorts, t-shirts, or used the swim suits.
It was cold -- in the upper 50's low 60's, and it had rained quite a bit before we had arrived. At night it dropped into the 40's. Hopefully when you go (you might have already left) it will be warm and sunny!!!