been to bkk 3 times & 3-4 days i would say is sufficent, make sure you do the FLOATING MARKET & BRIDGE/RIVER KWAI, cannot belive you will be missing koh samui out of your itinery, after bkk, phuket & pattaya you would have appriciated the laid back scene, but still with plenty nightlife & bg's, great beaches and fantastic massages. a heads up for bkk check out
Coming Soon... & remember never go upstairs in patpong rd 1/2