I booked the "Temple and River of Kings" tour through Intrepid, and met Gof, the tour leader for the tour. He was very knowledgable and fun and added a personal touch, even with recommending a place for lunch!
We took a long tail boat along the canal to see house boats and temples from the river, Gof bought bread to feed the fish (it was a frenzy!), then he led us around the reclining buddha temple Wat Pho (really beautiful). By this time it was a very hot day and Gof bought us cold water to drink before we took a tuk tuk to the Grand Palace to see the Emerald buddha.
He was friendly throughout, sharing tips and helping us to respect the location customs. Finally we took a local bus back to the Khaosan area. An enjoyable and eventful morning, definitely worth doing!