Stayed in the Shangri-La when honeymooning there in 2000, was a really nice hotel. At the time it was very reasonable given the quality (5 star) and service, the food was a bit expensive but there were also nice restaurants nearby. It is on the river, a river room view comes with nice views over Bangkok. Also easy access to some of the main temples (Wat-po and the Grand Palace) and otehr attractions. The Skytrain (Bangkok's eleveted metro) station is also nearby.