If you've ever been to Bangkok, you know that there is an immense variety of just everything there... truly the crossroads of SE Asia. When it comes to food selection, you just have to think of what you want to eat and then go find it b/c chances are high that it's not far from where you are standing... I enjoy eating in some of the more upscale shopping centers as the ambiance is usually outstanding. The people watching is also pretty interesting in most places throughout Bangkok - some areas much more than others, of course.
When it comes to selecting the right hotel to stay at - it really pays to do some serious research and get a lot of opinions before you book your room. There are so many things to consider that we cannot even begin to address them all so we suggest reviewing this article about Bangkok Hotels as a good primer.
Have a great trip!