pgaa - welcome to FT! This topic has been discussed many, many times even in the last year. I suggest you have a read at the various threads then post back if you need any further help on specific items.

In general, it helps to flesh out queries on this board with some specifics:
How many people are travelling?
Any kids?
Do you need to be near any specific location?
How long are you staying (affects how close you need to be to the action)?
Have you been to BKK before?
How old are you / do you prefer modern or traditional style?
What sort of room are you after - standard room or suite?
etc