Recommend Siam Paragon for food... amazing select of restaurants... my favourites being the Roast Duck & Crispy Pork @ MK and also The Chicken with Basil Salad at Ootoya....
And Mos Burger is pretty good
Also recommend you head over to Huay Kwang and get yourself a Soapy Massage at Nataree... that should kill a few hours for ya...lol