Found this great site couple of months back. combines all the big booking sites, agoda, booking.com etc. makes life allot easier and quicker to find the best deal on your stay 5555

hotelscombined.com.au
Compare Hotel Prices - Best Hotel Deals Guaranteed

I pretty much use this site to book all my hotels except (Raming lodge in chiang mai).
If you want the best deal on raming lodge. I found sawadee.com the best, they also give you the option of paying the small deposit or you can pay the full payment upfront, which i like allot.

sawadee.com
Sawadee.com - Thailand hotel booking at discount rates.