Cruised on Navigator in January 2007. They had soap by sink and in shower, and a blend of shampoo and conditioner in a dispenser in the shower, but a note said we could ask for separate shampoo and conditioner if we wanted. We had brought 3 oz of each anyway.
Towels in room were enough, but we brought our own for shore use.
Our massive amount of luggage fit easily under our bed and some (emergency stuff and shoes) we left in the bag to unpack if (and when) needed.
Have a great cruise. Wish we could join you.