Not sure if this posting is in time before you get into country but I also like Phachara Suites. It is a serviced apartment and you get more room and comfort for the same price you would pay at the Marriott or Sheraton.
Check out this link I posted on Phachara, http://www.bangkok-addicts.com/forum/topic/1108-4-5-hotel-or-similar/page__st__12. No joiner fee (guest friendly) and just think about the money you save on the room can go to your entertainment.
Sure there's others. I recommend Agoda.com, for deals and ratings. Plug in your dates and click Sukhomvit filter. Stay between Soi 4 and Soi 22 hotels.
Good luck.