My BKK picks are:
Sala Rim Naam, at the Oriental Hotel, 66.2.437.6221. My first trip there for the lunch buffet had me in a goosebump fit! Wonderful.
Somboon Seafood, 169/7-11 Surawong Rd., opposite Peugeot showroom, Bangrak, Bangkok 10500, 233.3104, 234.4499 (also in Bantadthong and Ratchada). The best crab curry I've ever had.
Ton Po, Phra Atit Rd. No phone. Outdoor (on a veranda) riverside dining on the Chao Phraya. We quite liked the haw moke plaa (curried fish custard, thickened with coconut cream and steamed in banana leaves), but one or two of the other dishes were too funky - even for me. It'd help to go with someone who REALLY knows Thai cuisine.
Prachak, 1415 Charoen Krung (New Road), Silom Bansak, 02.234.3755. No-frills restaurant. Difficult to find; I think it's near the Shangri-La and across from the Robinson Department Store between Sathorn Rd. and Silom Rd. (it's a slightly large range; if anyone finds a more precise intersection, let me know). The red pork (moo dang) and roast duck (ped) are the more popular dishes here. No credit cards; one of the cheapest meals of your life. Also, watch out for the spicy soup which Peter & I almost managed to finish (as the waitpeople watched in amazement & amusement while we sweated).
Thanying, 10 Pramuan Rd, Silom, Bangrak, Bangkok, 236.4361, 235.0371, F: 635.0113. Nice atmosphere (and food, of course!).
Spice Market, in the Regent Hotel, 155 Rajadamri Road. Good food and a nice atmosphere. Calming after a day in BKK traffic. I believe they serve nam doc mai, Thai mango with sticky rice & coconut milk.