Although I think sawadee are great they only fo Thailand, and for last minute we use
http://www.asiaoz.com/thailand_hotels.html
offers choices to compare, Sawadee rates plus Hotelclub and hotels2thailand ( though I go for Sawadee because of not having to upfront more than 1 night and being able to make request for free ) Ratestogo is Australian based and very good, another 'bonus' is that you only pay I think 12% deposit (!!) and a nominal couple of $ you pay the rest at the hotel, that is a big plus. You get your vouvher email and you pay all the rest of the money 'at the hotel', so you are only putting down 12%.
We used for recent Australia trip and worked clockwork and got huge savings.
Just remember the room nights need to be within 28 days, but at the moment you are close to that it is worth waiting a few days.

These are for first few days of feb that are now showing ) Amora at Bangtao ( used to be Rydges - Australian hotel group )US$ 75, Pool view rooms overlooking pool $99.
BW premiere Bangtao now down to $ 81 ( about 2,790 ) for seaview

right - am not booking yet - the rates are very good for the last days of jan/feb on many hotels. thanks JamesA!!