At one time I liked the funky Shanti Lodge, in the Dusit area (near the National Library). I sometimes still stay at the cheaper Taewez Guesthouse a few doors down @ 300THB for a double/fan/shared bathroom.

A few blocks from Khao San Rd, is the Wild Orchid. Open air lobby has a super atmosphere, but I've not seen the rooms or the prices. http://www.khaosanroad.com/directory...listing_id=198