bought a Samsung LED 40D5000 from Bangkok late last month. cost me around 18700 THB (excluding the 7% VAT refund). (now that's at least 45-50% cheaper than in India!!!)
bought it from best buy in Pantip Plaza. the guy with the small shop that jhonweed mentioned was selling it for even cheaper: ~17800 THB but i wasn't too comfortable dealing with him. the price for the 40D5000 in official Samsung showrooms was ~20,000 THB.
There are lots of malls where yo can pick up TVs from in Bangkok and depending upon how hard you search for the 'best deal' you'll not save more than Rs. 1000. Point being, don't waste your time going through 10 different shops checking for prices cos at the end of the day you'll still save 45-50%. Go to any of the places mentioned in the earlier posts and you should be good.
One thing to keep in mind is that nobody will give you an international warranty card, neither the official nor the grey market dealers. The warranty card will be local and you will have to get register the serial number online and get the warranty claim. I wasted an entire day in this every dealer promised international warranty and when I asked them for more details they never gave me a straight answer; (and language is BIG BIG barrier).
Made one crucial error: we didn't get the warranty card stamped in a hurry while trying to not miss our flight and also could not take a copy of the bill. the original bill was retained at the VAT refund counter.
So make sure you get the WARRANTY CARD STAMPED and take a BILL COPY for future reference. and if anyone is travelling to bangkok soon and is willing to help a fellow member please let me know