I am not a city person so I only take in a day of BKK per trip. In 3 trips to LOS I have not stayed in BKK a total of 9 nights yet. It is definitely a place to check out IMO while you are there, but not for too long.
Pattaya seemed to cost less than BKK on hotels, girls, beer, food etc(w/out really shopping around).
What ever you decide I am sure you will have fun.
