I have been using priceline for years and love it. Biddingfortravel takes much of the guesswork out of the process, and I can usually be 90% sure that I will be able to get a specific hotel.

I just got the Beverly Hills Hilton for next Sunday night for $82. I also got the Hilton LAX for next Monday night for $40. Both of those represent savings of more than $100/night, so if neither honor my HHonors Gold, that $100 will buy plenty of breakfasts. Half the time I am able to have my hilton # input and when I make a phone call from the room (for an incidental) I get stay credit.