I also enjoy the Hilton at AMS, but it is quite expensive. If you are looking to stay cheaper, there is a hotel called Citizen M on the airport property (about a block or two walk from the terminal). I stayed there for under $100 US late last year (includes free Internet).

Citizen M is an uber-modern hotel. The style may not be for everyone, so you might want to check it out online before you go. The rooms are small by design, but are well-designed, clean, and comfortable. It is a quirky place and very high tech hotel -- I've never stayed in anything like it. I spent a couple of hours playing with all of the gadgets and controls in the room. Its a fun place to stay -- especially for one night!