Donna, the Intercontinental, Marriott, and Pulitzer(formerly Sheraton) are all listed as the only 5 star hotels on bidding for travel, which is the look to place for finding what hotels Priceline is using. I have made SO many good deals on PL, because I usually do it for airport hotels and don't care within the ** rating which one I use. Might be worth a look, if you would be happy with either of those chains. BFT has a message board where people tell what they paid for what hotels, and the dates. I always start bidding at less than half the website price. You can always re-bid.

Marriott Amsterdam [reviews]
Hotel Pulitzer (formerly Sheraton)
InterContinental Amstel Amsterdam (another possible hotel; not reported yet)