I also like to pack some bubble wrap. Comes in handy if I buy something breakable and if I don't need it I just leave it behind. That also frees up room in the luggage. Our local Target has lots of travel sizes of things so I buy a travel size of laundry liquid. Costs me 75cents and does 2 loads, opposed to paying $1 for a box on board that only does 1 load. Throw in a couple of fabric softener sheets as well.
I make up a little 'first aid' kit as well. The usual things plus sudafed and a Tide to Go pen for stains on clothes, should they happen.