One thing I haven't seen mentioned is extra hangers. There is never enough in the hotel closet, and not enough room in the drawers for all of our clothes. We usually stay 10+ days, so I pack a lot of clothes. The best hangers I have found are Huggable Hangers. They are slim and light, for packing. I have used them for our last 3 trips. They have been very useful.
Also I have a 2 yr. old, so I always pack disposable bibs, disposable stick on place mats, and disposable plastic toddler utensils and sippy cups.
One last tip: Our last 2 trips I have shipped a box to our resort full of snacks, water, paper towels and other odds and ends that we will use up before the end of our trip.