The Mercure hotel located between gates D and E is the most ingenious feature for transit pax at Schipol airport. Single rooms are €80 a night from 8pm to 8am. I've stayed there a couple of times before catching a morning flight and it's nice - actually bit spooky too at night - to stroll around the terminal without having to rush for boarding. Be aware it's not the same Mercure out on the airport road which travellers get confused with.