If you have only two days in Bangkok, I'd skip the floating market and concentrate on the Grand Place, Wat Pho, the river, and Chinatown.
Day One: Grand Palace, Wat Phra Kaew (the Emerald Buddha), and Wat Pho. Wat Pho is the largest and most impressive temple in Bangkok, famed for its huge gold-plated reclining Buddha measuring about 50 meters long. Wat Pho is also Bangkok's main training center for masseuses. Thai massage at Wat Pho is a must while you're in Bangkok. Cost is about 120 baht for half an hour or 200 baht per hour. For dinner, go to Sirocco or Vertigo.
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Day Two: Chaophraya River and Khlong tour by long tail speed boat. Visit also Thonburi Khlongs, Wat Arun, and the Royal Barges Museum. Visit the Golden Buddha temple around 4 PM and then have dinner at Yaowarat Road in Chinatown.
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